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Title: Water And Ion Transport Through The Glass Transition In Polyelectrolyte Complexes.
Creator: Abou Shaheen, Samir, Yang, Mo, Chen, Banghao, Schlenoff, Joseph B.
Abstract/Description: Polyelectrolyte complexes or coacervates, PECs, represent one of the many families of ion-containing polymers proposed or in use for applications requiring mobile ions, including fuel cells, water purification, and rechargeable batteries. Interest in these materials has focused on how ion transport is coupled to, and limited by, polymer dynamics, which slow considerably below the glass transition, T-g. Unlike many other polymer systems, ion conductivity in hydrated PECs remains high above and...
Show morePolyelectrolyte complexes or coacervates, PECs, represent one of the many families of ion-containing polymers proposed or in use for applications requiring mobile ions, including fuel cells, water purification, and rechargeable batteries. Interest in these materials has focused on how ion transport is coupled to, and limited by, polymer dynamics, which slow considerably below the glass transition, T-g. Unlike many other polymer systems, ion conductivity in hydrated PECs remains high above and below T-g. In this work, we investigate the transport of water and ions within a PEC as the polymer host passes through T-g. We find no evidence of a response in the transport of water and small univalent ions, such as Na+ and Cl-, as the hydrated PEC goes through T-g. In contrast, triple-charged ions ferricyanide and ruthenium hexamine experience a second-order change in transport rate at T-g. This response is interpreted to show that these ions engage enough polyelectrolyte repeat units to experience the highly localized cooperative rearrangement thought to be responsible for the glass transition.
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Date Issued: 2020-07-28
Identifier: FSU_libsubv1_wos_000557753300007, 10.1021/acs.chemmater.0c01217
Format: Citation

Title: Precision Doping of Polyelectrolyte Complexes: Insight on the Role of Ions.
Creator: Schlenoff, Joseph
Abstract/Description: The properties of polyelectrolyte complexes and coacervates, both termed PECs, are influenced strongly by their ion and water content. Water plasticizes PECs, reducing their modulus and glass transition temperature, Tg. In this work, a hydrated PEC with a Tg near room temperature, made from poly(diallyldimethylammonium), PDADMA, and poly(styrene sulfonate), PSS, was precisely doped with 22Na-labeled sodium salts along a Hofmeister series. A distinctive change in the rate of doping versus...
Show moreThe properties of polyelectrolyte complexes and coacervates, both termed PECs, are influenced strongly by their ion and water content. Water plasticizes PECs, reducing their modulus and glass transition temperature, Tg. In this work, a hydrated PEC with a Tg near room temperature, made from poly(diallyldimethylammonium), PDADMA, and poly(styrene sulfonate), PSS, was precisely doped with 22Na-labeled sodium salts along a Hofmeister series. A distinctive change in the rate of doping versus added salt concentration was observed for all salts. This transition was interpreted to reflect a change in ion-accessible volume coinciding with a change in the role of added salt from counterions for the polyelectrolytes, paired directly and within one water molecule of the charge on the polymer backbone, to a mix of counterions and co-ions, which do not have a specific location within the PEC. Isothermal calorimety for PEC made in, and doped by, NaCl showed two clear regions for enthaply change, ΔH, before and after the doping transition. The higher ΔH region was correlated with the counterion role, an indirect measure of the location of ions within the PEC
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Date Issued: 2020-06-23
Identifier: FSU_libsubv1_scholarship_submission_1607020488_75d87d43, doi.org/10.1021/acs.macromol.0c00965
Format: Citation

Title: Elucidating The Role Of Surface Coating In The Promotion Or Prevention Of Protein Corona Around Quantum Dots.
Creator: Perng, Woody, Palui, Goutam, Wang, Wentao, Mattoussi, Hedi
Abstract/Description: Nonspecific interactions in biological media can lead to the formation of a protein corona around nanocolloids, which tends to alter their behavior and limit their effectiveness when used as probes for imaging or sensing applications. Yet, understanding the corona buildup has been challenging. We hereby investigate these interactions using luminescent quantum dots (QDs) as a model nanocolloid system, where we carefully vary the nature of the hydrophilic block in the surface coating, while...
Show moreNonspecific interactions in biological media can lead to the formation of a protein corona around nanocolloids, which tends to alter their behavior and limit their effectiveness when used as probes for imaging or sensing applications. Yet, understanding the corona buildup has been challenging. We hereby investigate these interactions using luminescent quantum dots (QDs) as a model nanocolloid system, where we carefully vary the nature of the hydrophilic block in the surface coating, while maintaining the same dihydrolipoic acid (DHLA) bidentate coordinating motif. We first use agarose gel electrophoresis to track changes in the mobility shift upon exposure of the QDs to protein-rich media. We find that QDs capped with DHLA (which presents a hydrophobic alkyl chain terminated with a carboxyl group) promote corona formation, in a concentration-dependent manner. However, when a polyethylene glycol block or a zwitterion group is appended onto DHLA, it yields a coating that prevents corona buildup. Our results clearly confirm that nonspecific interactions with protein-rich media are strongly dependent on the nature of the hydrophilic motif used. Additional gel experiments using SDS-PAGE have allowed further characterization of the corona protein, and showed that mainly a soft corona forms around the DHLA-capped QDs. These findings will be highly informative when designing nanocolloids that can find potential use in biological applications.
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Date Issued: 2019-09-01
Identifier: FSU_libsubv1_wos_000487180000022, 10.1021/acs.bioconjchem.9b00549
Format: Citation

Title: Control Of Hexamerization, Assembly, And Excluded Strand Specificity For The Sulfolobus Solfataricus Mcm Helicase.
Creator: Graham, Brian W., Bougoulias, Michael E., Dodge, Katie L., Thaxton, Carly T., Olaso, Danae, Tao, Yeqing, Young, Nicolas L., Marshall, Alan G., Trakselis, Michael A.
Abstract/Description: A growing body of evidence supports a steric exclusion and wrapping model for DNA unwinding in which hexameric helicases interact with the excluded single-stranded DNA (ssDNA) in addition to the encircled strand. Interactions with the excluded ssDNA have been shown to be mediated primarily by electrostatic interactions, but base stacking with surface-exposed tyrosine residues is an alternative hypothesis. Here, we mutated several external tyrosine and positively charged residues from full...
Show moreA growing body of evidence supports a steric exclusion and wrapping model for DNA unwinding in which hexameric helicases interact with the excluded single-stranded DNA (ssDNA) in addition to the encircled strand. Interactions with the excluded ssDNA have been shown to be mediated primarily by electrostatic interactions, but base stacking with surface-exposed tyrosine residues is an alternative hypothesis. Here, we mutated several external tyrosine and positively charged residues from full-length Sulfolobus solfataricus MCM along the proposed path of excluded strand binding and assessed their impact on DNA unwinding. Four of the five tyrosine residues had significant decreases in their level of unwinding, and one, Y519A, located within the alpha/beta-alpha linker region of the C-terminal domain, had the most severe perturbation attributed to the disruption of hexamerization. The Y519 mutant exhibits an enhanced and stabilized secondary structure that is modulated by temperature, binding DNA with a higher apparent affinity and suggesting a pathway for hexameric assembly. Hydrogen/deuterium exchange coupled to mass spectrometry was used to map deuterium uptake differences between wild-type and Y519A apo structures highlighting global differences in solvent accessible areas consistent with altered quaternary structure. Two of the five electrostatic mutants had significantly reduced levels of DNA unwinding and combined with previous mutations better define the exterior binding path. The importance of the electrostatic excluded strand interaction was confirmed by use of morpholino DNA substrates that showed analogous reduced unwinding rates. These results better define the hexameric assembly and influence of the excluded strand interactions in controlling DNA unwinding by the archaeal MCM complex.
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Date Issued: 2018-10-02
Identifier: FSU_libsubv1_wos_000446542800005, 10.1021/acs.biochem.8b00766
Format: Citation

Title: Tropical Peatland Carbon Storage Linked To Global Latitudinal Trends In Peat Recalcitrance.
Creator: Hodgkins, Suzanne B., Richardson, Curtis J., Dommain, Rene, Wang, Hongjun, Glaser, Paul H., Verbeke, Brittany, Winkler, B. Rose, Cobb, Alexander R., Rich, Virginia I.,...
Show moreHodgkins, Suzanne B., Richardson, Curtis J., Dommain, Rene, Wang, Hongjun, Glaser, Paul H., Verbeke, Brittany, Winkler, B. Rose, Cobb, Alexander R., Rich, Virginia I., Missilmani, Malak, Flanagan, Neal, Ho, Mengchi, Hoyt, Alison M., Harvey, Charles F., Vining, S. Rose, Hough, Moira A., Moore, Tim R., Richard, Pierre J. H., De la Cruz, Florentino B., Toufaily, Joumana, Hamdan, Rasha, Cooper, William T., Chanton, Jeffrey P.
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Abstract/Description: Peatlands represent large terrestrial carbon banks. Given that most peat accumulates in boreal regions, where low temperatures and water saturation preserve organic matter, the existence of peat in (sub)tropical regions remains enigmatic. Here we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Near-surface low-latitude peat has lower carbohydrate and greater aromatic content than near-surface high-latitude peat, creating a reduced oxidation...
Show morePeatlands represent large terrestrial carbon banks. Given that most peat accumulates in boreal regions, where low temperatures and water saturation preserve organic matter, the existence of peat in (sub)tropical regions remains enigmatic. Here we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Near-surface low-latitude peat has lower carbohydrate and greater aromatic content than near-surface high-latitude peat, creating a reduced oxidation state and resulting recalcitrance. This recalcitrance allows peat to persist in the (sub)tropics despite warm temperatures. Because we observed similar declines in carbohydrate content with depth in high-latitude peat, our data explain recent field-scale deep peat warming experiments in which catotelm (deeper) peat remained stable despite temperature increases up to 9 degrees C. We suggest that high-latitude deep peat reservoirs may be stabilized in the face of climate change by their ultimately lower carbohydrate and higher aromatic composition, similar to tropical peats.
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Date Issued: 2018-09-07
Identifier: FSU_libsubv1_wos_000444014100015, 10.1038/s41467-018-06050-2
Format: Citation

Title: Tropical peatland carbon storage linked to global latitudinal trends in peat recalcitrance.
Creator: Hodgkins, Suzanne B, Richardson, Curtis J, Dommain, René, Wang, Hongjun, Glaser, Paul H, Verbeke, Brittany, Winkler, B Rose, Cobb, Alexander R, Rich, Virginia I, Missilmani,...
Show moreHodgkins, Suzanne B, Richardson, Curtis J, Dommain, René, Wang, Hongjun, Glaser, Paul H, Verbeke, Brittany, Winkler, B Rose, Cobb, Alexander R, Rich, Virginia I, Missilmani, Malak, Flanagan, Neal, Ho, Mengchi, Hoyt, Alison M, Harvey, Charles F, Vining, S Rose, Hough, Moira A, Moore, Tim R, Richard, Pierre J H, De La Cruz, Florentino B, Toufaily, Joumana, Hamdan, Rasha, Cooper, William T, Chanton, Jeffrey P
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Abstract/Description: Peatlands represent large terrestrial carbon banks. Given that most peat accumulates in boreal regions, where low temperatures and water saturation preserve organic matter, the existence of peat in (sub)tropical regions remains enigmatic. Here we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Near-surface low-latitude peat has lower carbohydrate and greater aromatic content than near-surface high-latitude peat, creating a reduced oxidation...
Show morePeatlands represent large terrestrial carbon banks. Given that most peat accumulates in boreal regions, where low temperatures and water saturation preserve organic matter, the existence of peat in (sub)tropical regions remains enigmatic. Here we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Near-surface low-latitude peat has lower carbohydrate and greater aromatic content than near-surface high-latitude peat, creating a reduced oxidation state and resulting recalcitrance. This recalcitrance allows peat to persist in the (sub)tropics despite warm temperatures. Because we observed similar declines in carbohydrate content with depth in high-latitude peat, our data explain recent field-scale deep peat warming experiments in which catotelm (deeper) peat remained stable despite temperature increases up to 9 °C. We suggest that high-latitude deep peat reservoirs may be stabilized in the face of climate change by their ultimately lower carbohydrate and higher aromatic composition, similar to tropical peats.
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Date Issued: 2018-09-07
Identifier: FSU_pmch_30194308, 10.1038/s41467-018-06050-2, PMC6128871, 30194308, 30194308, 10.1038/s41467-018-06050-2
Format: Citation

Title: Pathogenic Tfg Mutations Underlying Hereditary Spastic Paraplegia Impair Secretory Protein Trafficking And Axon Fasciculation.
Creator: Slosarek, Erin L., Schuh, Amber L., Pustova, Iryna, Johnson, Adam, Bird, Jennifer, Johnson, Matthew, Frankel, E. B., Bhattacharya, Nilakshee, Hanna, Michael G., Burke, Jordan E....
Show moreSlosarek, Erin L., Schuh, Amber L., Pustova, Iryna, Johnson, Adam, Bird, Jennifer, Johnson, Matthew, Frankel, E. B., Bhattacharya, Nilakshee, Hanna, Michael G., Burke, Jordan E., Ruhl, David A., Quinney, Kyle, Block, Samuel, Peotter, Jennifer L., Chapman, Edwin R., Sheets, Michael D., Butcher, Samuel E., Stagg, Scott M., Audhya, Anjon
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Abstract/Description: Length-dependent axonopathy of the corticospinal tract causes lower limb spasticity and is characteristic of several neurological disorders, including hereditary spastic paraplegia (HSP) and amyotrophic lateral sclerosis. Mutations in Trk-fused gene (TFG) have been implicated in both diseases, but the pathomechanisms by which these alterations cause neuropathy remain unclear. Here, we biochemically and genetically define the impact of a mutation within the TFG coiled-coil domain, which...
Show moreLength-dependent axonopathy of the corticospinal tract causes lower limb spasticity and is characteristic of several neurological disorders, including hereditary spastic paraplegia (HSP) and amyotrophic lateral sclerosis. Mutations in Trk-fused gene (TFG) have been implicated in both diseases, but the pathomechanisms by which these alterations cause neuropathy remain unclear. Here, we biochemically and genetically define the impact of a mutation within the TFG coiled-coil domain, which underlies early-onset forms of HSP. We find that the TFG (p.R106C) mutation alters compaction of TFG ring complexes, which play a critical role in the export of cargoes from the endoplasmic reticulum (ER). Using CRISPR-mediated genome editing, we engineered human stem cells that express the mutant form of TFG at endogenous levels and identified specific defects in secretion from the ER and axon fasciculation following neuronal differentiation. Together, our data highlight a key role for TFG-mediated protein transport in the pathogenesis of HSP.
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Date Issued: 2018-08-28
Identifier: FSU_libsubv1_wos_000442923900005, 10.1016/j.celrep.2018.07.081
Format: Citation

Title: Pathogenic TFG Mutations Underlying Hereditary Spastic Paraplegia Impair Secretory Protein Trafficking and Axon Fasciculation.
Creator: Slosarek, Erin L, Schuh, Amber L, Pustova, Iryna, Johnson, Adam, Bird, Jennifer, Johnson, Matthew, Frankel, E B, Bhattacharya, Nilakshee, Hanna, Michael G, Burke, Jordan E, Ruhl...
Show moreSlosarek, Erin L, Schuh, Amber L, Pustova, Iryna, Johnson, Adam, Bird, Jennifer, Johnson, Matthew, Frankel, E B, Bhattacharya, Nilakshee, Hanna, Michael G, Burke, Jordan E, Ruhl, David A, Quinney, Kyle, Block, Samuel, Peotter, Jennifer L, Chapman, Edwin R, Sheets, Michael D, Butcher, Samuel E, Stagg, Scott M, Audhya, Anjon
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Abstract/Description: Length-dependent axonopathy of the corticospinal tract causes lower limb spasticity and is characteristic of several neurological disorders, including hereditary spastic paraplegia (HSP) and amyotrophic lateral sclerosis. Mutations in Trk-fused gene (TFG) have been implicated in both diseases, but the pathomechanisms by which these alterations cause neuropathy remain unclear. Here, we biochemically and genetically define the impact of a mutation within the TFG coiled-coil domain, which...
Show moreLength-dependent axonopathy of the corticospinal tract causes lower limb spasticity and is characteristic of several neurological disorders, including hereditary spastic paraplegia (HSP) and amyotrophic lateral sclerosis. Mutations in Trk-fused gene (TFG) have been implicated in both diseases, but the pathomechanisms by which these alterations cause neuropathy remain unclear. Here, we biochemically and genetically define the impact of a mutation within the TFG coiled-coil domain, which underlies early-onset forms of HSP. We find that the TFG (p.R106C) mutation alters compaction of TFG ring complexes, which play a critical role in the export of cargoes from the endoplasmic reticulum (ER). Using CRISPR-mediated genome editing, we engineered human stem cells that express the mutant form of TFG at endogenous levels and identified specific defects in secretion from the ER and axon fasciculation following neuronal differentiation. Together, our data highlight a key role for TFG-mediated protein transport in the pathogenesis of HSP.
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Date Issued: 2018-08-28
Identifier: FSU_pmch_30157421, 10.1016/j.celrep.2018.07.081, PMC6152936, 30157421, 30157421, S2211-1247(18)31199-9
Format: Citation

Title: (tco4-)-tc-99 Remediation By A Cationic Polymeric Network.
Creator: Li, Jie, Dai, Xing, Zhu, Lin, Xu, Chao, Zhang, Duo, Silver, Mark A., Li, Peng, Chen, Lanhua, Li, Yongzhong, Zuo, Douwen, Zhang, Hui, Xiao, Chengliang, Chen, Jing, Diwu, Juan,...
Show moreLi, Jie, Dai, Xing, Zhu, Lin, Xu, Chao, Zhang, Duo, Silver, Mark A., Li, Peng, Chen, Lanhua, Li, Yongzhong, Zuo, Douwen, Zhang, Hui, Xiao, Chengliang, Chen, Jing, Diwu, Juan, Farha, Omar K., Albrecht-Schmitt, Thomas E., Chai, Zhifang, Wang, Shuao
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Abstract/Description: Direct removal of (TcO4-)-Tc-99 from the highly acidic solution of used nuclear fuel is highly beneficial for the recovery of uranium and plutonium and more importantly aids in the elimination of Tc-99 discharge into the environment. However, this task represents a huge challenge given the combined extreme conditions of super acidity, high ionic strength, and strong radiation field. Here we overcome this challenge using a cationic polymeric network with significant TcO4- uptake capabilities...
Show moreDirect removal of (TcO4-)-Tc-99 from the highly acidic solution of used nuclear fuel is highly beneficial for the recovery of uranium and plutonium and more importantly aids in the elimination of Tc-99 discharge into the environment. However, this task represents a huge challenge given the combined extreme conditions of super acidity, high ionic strength, and strong radiation field. Here we overcome this challenge using a cationic polymeric network with significant TcO4- uptake capabilities in four aspects: the fastest sorption kinetics, the highest sorption capacity, the most promising uptake performance from highly acidic solutions, and excellent radiation-resistance and hydrolytic stability among all anion sorbent materials reported. In addition, this material is fully recyclable for multiple sorption/desorption trials, making it extremely attractive for waste partitioning and emergency remediation. The excellent TcO4- uptake capability is elucidated by X-ray absorption spectroscopy, solid-state NMR measurement, and density functional theory analysis on anion coordination and bonding.
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Date Issued: 2018-08-01
Identifier: FSU_libsubv1_wos_000440413500007, 10.1038/s41467-018-05380-5
Format: Citation

Title: TcO remediation by a cationic polymeric network.
Creator: Li, Jie, Dai, Xing, Zhu, Lin, Xu, Chao, Zhang, Duo, Silver, Mark A, Li, Peng, Chen, Lanhua, Li, Yongzhong, Zuo, Douwen, Zhang, Hui, Xiao, Chengliang, Chen, Jing, Diwu, Juan,...
Show moreLi, Jie, Dai, Xing, Zhu, Lin, Xu, Chao, Zhang, Duo, Silver, Mark A, Li, Peng, Chen, Lanhua, Li, Yongzhong, Zuo, Douwen, Zhang, Hui, Xiao, Chengliang, Chen, Jing, Diwu, Juan, Farha, Omar K, Albrecht-Schmitt, Thomas E, Chai, Zhifang, Wang, Shuao
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Abstract/Description: Direct removal of TcO from the highly acidic solution of used nuclear fuel is highly beneficial for the recovery of uranium and plutonium and more importantly aids in the elimination of Tc discharge into the environment. However, this task represents a huge challenge given the combined extreme conditions of super acidity, high ionic strength, and strong radiation field. Here we overcome this challenge using a cationic polymeric network with significant TcO uptake capabilities in four aspects:...
Show moreDirect removal of TcO from the highly acidic solution of used nuclear fuel is highly beneficial for the recovery of uranium and plutonium and more importantly aids in the elimination of Tc discharge into the environment. However, this task represents a huge challenge given the combined extreme conditions of super acidity, high ionic strength, and strong radiation field. Here we overcome this challenge using a cationic polymeric network with significant TcO uptake capabilities in four aspects: the fastest sorption kinetics, the highest sorption capacity, the most promising uptake performance from highly acidic solutions, and excellent radiation-resistance and hydrolytic stability among all anion sorbent materials reported. In addition, this material is fully recyclable for multiple sorption/desorption trials, making it extremely attractive for waste partitioning and emergency remediation. The excellent TcO uptake capability is elucidated by X-ray absorption spectroscopy, solid-state NMR measurement, and density functional theory analysis on anion coordination and bonding.
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Date Issued: 2018-08-01
Identifier: FSU_pmch_30068903, 10.1038/s41467-018-05380-5, PMC6070552, 30068903, 30068903, 10.1038/s41467-018-05380-5
Format: Citation

Title: Photochemistry Of The Stilbenes In Methanol. Trapping The Common Phantom Singlet State.
Creator: Saltiel, Jack, Gupta, Shipra
Abstract/Description: A comparative study of the photochemistry of cis- and trans-stilbene in methanol shows that both isomers undergo methanol photoaddition giving similar yields of a-methoxybibenzyl in competition with cis-trans photoisomerization. Methanol addition occurs primarily following torsional relaxation of the lowest excited singlet states of each isomer, (l)c* and (1)t*, to a common twisted singlet excited state intermediate, (1)p*, initially called the phantom singlet state. The addition is...
Show moreA comparative study of the photochemistry of cis- and trans-stilbene in methanol shows that both isomers undergo methanol photoaddition giving similar yields of a-methoxybibenzyl in competition with cis-trans photoisomerization. Methanol addition occurs primarily following torsional relaxation of the lowest excited singlet states of each isomer, (l)c* and (1)t*, to a common twisted singlet excited state intermediate, (1)p*, initially called the phantom singlet state. The addition is consistent with the zwitterionic character of (1)p. Ether forms by direct 1,2-addition of CH 3 OH to the central carbon atoms and by 1,1-addition following rearrangement to 1-benzyl-1-phenylcarbene. Use of CD3OD and GC/MS (gas chromatographic/mass spectroscopic) analysis of the ether products revealed that the ratio of carbene/direct addition pathways is higher starting from cis-stilbene. We conclude that (1)p* formed from (1)c* is hotter than (1)p* formed from (1)t*. Surprisingly, except for favoring the carbene pathway, the use of higher energy photons (254 vs 313 nm) does not affect the overall ether quantum yield starting from cis-stilbene but significantly enhances both pathways starting from trans-stilbene. It appears that carbene formation and direct methanol addition to higher trans-stilbene excited state(s) compete with relaxation to S-1. Substitution of D for the vinyl Hs of stilbene enhances the direct addition pathway more than 2-fold and strongly suppresses the carbene insertion pathway, revealing a large, k(pc)(d0)/k(pe)(d2) : = 6.3, primary deuterium isotope effect in the carbene rearrangement. The 2-fold increase in the ether quantum yield is due primarily to a 2.75-fold increase in the lifetime of (1)p* on deuterium substitution of the vinyl hydrogens.
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Date Issued: 2018-07-26
Identifier: FSU_libsubv1_wos_000440519300008, 10.1021/acs.jpca.8b04011
Format: Citation

Title: Modular Access To Functionalized 5-8-5 Fused Ring Systems Via A Photoinduced Cycloisomerization Reaction.
Creator: Salvati, Anna E., Law, James A., Liriano, Josue, Frederich, James H.
Abstract/Description: A 5-8-5 carbocyclic ring system forms the core of over 30 distinct natural products. Several members of this family have gained attention for their diverse activity in cell culture. In these cases, biological function is mediated by the arrangement of substituents around a conserved 5-8-5 nucleus. Despite the potential applications of this privileged substructure in medicinal chemistry, modular strategies for its assembly are underdeveloped. Herein, we describe a cycloisomerization reaction...
Show moreA 5-8-5 carbocyclic ring system forms the core of over 30 distinct natural products. Several members of this family have gained attention for their diverse activity in cell culture. In these cases, biological function is mediated by the arrangement of substituents around a conserved 5-8-5 nucleus. Despite the potential applications of this privileged substructure in medicinal chemistry, modular strategies for its assembly are underdeveloped. Herein, we describe a cycloisomerization reaction that forms the 5-8-5 framework directly. This strategy uniquely allows access to gram quantities of this valuable scaffold in four steps.
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Date Issued: 2018-06-28
Identifier: FSU_libsubv1_wos_000436027800011, 10.1039/c8sc00999f
Format: Citation

Title: Ferromagnetic Quantum Critical Point In Cepd2p2 With Pd -> Ni Substitution.
Creator: Lai, Y., Bone, S. E., Minasian, S., Ferrier, M. G., Lezama-Pacheco, J., Mocko, V., Ditter, A. S., Kozimor, S. A., Seidler, G. T., Nelson, W. L., Chiu, Y.-C., Huang, K., Potter,...
Show moreLai, Y., Bone, S. E., Minasian, S., Ferrier, M. G., Lezama-Pacheco, J., Mocko, V., Ditter, A. S., Kozimor, S. A., Seidler, G. T., Nelson, W. L., Chiu, Y.-C., Huang, K., Potter, W., Graf, D., Albrecht-Schmitt, T. E., Baumbach, R. E.
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Abstract/Description: An investigation of the structural, thermodynamic, and electronic transport properties of the isoelectronic chemical substitution series Ce(Pd1-x Ni-x)(2)P-2 is reported, where a possible ferromagnetic quantum critical point is uncovered in the temperature-concentration (T-x) phase diagram. This behavior results from the simultaneous contraction of the unit cell volume, which tunes the relative strengths of the Kondo and Ruderman-KittelKasuya- Yosida (RKKY) interactions, and the introduction...
Show moreAn investigation of the structural, thermodynamic, and electronic transport properties of the isoelectronic chemical substitution series Ce(Pd1-x Ni-x)(2)P-2 is reported, where a possible ferromagnetic quantum critical point is uncovered in the temperature-concentration (T-x) phase diagram. This behavior results from the simultaneous contraction of the unit cell volume, which tunes the relative strengths of the Kondo and Ruderman-KittelKasuya- Yosida (RKKY) interactions, and the introduction of disorder through alloying. Near the critical region at x(cr) approximate to 0.7, the rate of contraction of the unit cell volume strengthens, indicating that the cerium f valence crosses over from trivalent to a noninteger value. Consistent with this picture, x-ray absorption spectroscopy measurements reveal that while CePd2P2 has a purely trivalent cerium f state, CeNi2P2 has a small (<10 %) tetravalent contribution. In a broad region around xcr, there is a breakdown of Fermi-liquid temperature dependences, signaling the influence of quantum critical fluctuations and disorder effects. Measurements of clean CePd2P2 furthermore showthat applied pressure has an initial effect similar to alloying on the ferromagnetic order. From these results, CePd2P2 emerges as a keystone system to test theories such as the Belitz-Kirkpatrick-Vojta model for ferromagnetic quantum criticality, where distinct behaviors are expected in the dirty and clean limits.
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Date Issued: 2018-06-06
Identifier: FSU_libsubv1_wos_000434256700002, 10.1103/PhysRevB.97.224406
Format: Citation

Title: A Rare Positively Charged Nicotinic Acid Disulfide: 2,2 '-dithiodinicotinic Acid Hydrochloride Monohydrate.
Creator: Chemey, Alexander T., McGuire, Chad M., Albrecht-Schmitt, Thomas E.
Abstract/Description: The title compound {systematic name: 3-carboxy-2-[2-(3-carboxypyridin-2-yl)disulfan-1-yl)]pyridin-1-ium chloride monohydrate}, C12H9N2O4S2+center dot Cl-center dot H2O, O, crystallizes in the triclinic space group P (1) over bar. A pair of 2-mercaptonicotinic acid moieties is connected by a 2,2'-disulfide bond with a dihedral angle of 78.79 (3)degrees. One of the N atom is protonated, as are both carboxylate groups, resulting in an overall +1 charge on the dimer. The structure comprises a...
Show moreThe title compound {systematic name: 3-carboxy-2-[2-(3-carboxypyridin-2-yl)disulfan-1-yl)]pyridin-1-ium chloride monohydrate}, C12H9N2O4S2+center dot Cl-center dot H2O, O, crystallizes in the triclinic space group P (1) over bar. A pair of 2-mercaptonicotinic acid moieties is connected by a 2,2'-disulfide bond with a dihedral angle of 78.79 (3)degrees. One of the N atom is protonated, as are both carboxylate groups, resulting in an overall +1 charge on the dimer. The structure comprises a zigzagging layer of the dimerized dithiodinicotinic acid rings, with charge-balancing chloride ions and water molecules between the layers. Hydrogen bonding between the chloride and water sites with the dimer appears to hold the structure together. Nearest neighbor nicotinic acid rings are offset when viewed down the a axis, suggesting no added stability from ring stacking. The asymmetric unit corresponds to the empirical formula of the compound, and it packs with two formula units per unit cell.
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Date Issued: 2018-06-01
Identifier: FSU_libsubv1_wos_000433880900013, 10.1107/S2056989018006916
Format: Citation

Title: Modular access to functionalized 5-8-5 fused ring systems a photoinduced cycloisomerization reaction.
Creator: Salvati, Anna E, Law, James A, Liriano, Josue, Frederich, James H
Abstract/Description: A 5-8-5 carbocyclic ring system forms the core of over 30 distinct natural products. Several members of this family have gained attention for their diverse activity in cell culture. In these cases, biological function is mediated by the arrangement of substituents around a conserved 5-8-5 nucleus. Despite the potential applications of this privileged substructure in medicinal chemistry, modular strategies for its assembly are underdeveloped. Herein, we describe a cycloisomerization reaction...
Show moreA 5-8-5 carbocyclic ring system forms the core of over 30 distinct natural products. Several members of this family have gained attention for their diverse activity in cell culture. In these cases, biological function is mediated by the arrangement of substituents around a conserved 5-8-5 nucleus. Despite the potential applications of this privileged substructure in medicinal chemistry, modular strategies for its assembly are underdeveloped. Herein, we describe a cycloisomerization reaction that forms the 5-8-5 framework directly. This strategy uniquely allows access to gram quantities of this valuable scaffold in four steps.
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Date Issued: 2018-05-25
Identifier: FSU_pmch_30009010, 10.1039/c8sc00999f, PMC6009507, 30009010, 30009010, c8sc00999f
Format: Citation

Title: A rare positively charged nicotinic acid di-sulfide: 2,2'-di-thio-dinicotinic acid hydro-chloride monohydrate..
Creator: Chemey, Alexander T, McGuire, Chad M, Albrecht-Schmitt, Thomas E
Abstract/Description: The title compound {systematic name: 3-carb-oxy-2-[2-(3-carb-oxy-pyridin-2-yl)disulfan-1-yl)]pyridin-1-ium chloride monohydrate}, CHNOS·Cl·HO, crystallizes in the triclinic space group . A pair of 2-mercaptonicotinic acid moieties is connected by a 2,2'-di-sulfide bond with a dihedral angle of 78.79 (3)°. One of the N atom is protonated, as are both carboxyl-ate groups, resulting in an overall +1 charge on the dimer. The structure comprises a zigzagging layer of the dimerized di-thio...
Show moreThe title compound {systematic name: 3-carb-oxy-2-[2-(3-carb-oxy-pyridin-2-yl)disulfan-1-yl)]pyridin-1-ium chloride monohydrate}, CHNOS·Cl·HO, crystallizes in the triclinic space group . A pair of 2-mercaptonicotinic acid moieties is connected by a 2,2'-di-sulfide bond with a dihedral angle of 78.79 (3)°. One of the N atom is protonated, as are both carboxyl-ate groups, resulting in an overall +1 charge on the dimer. The structure comprises a zigzagging layer of the dimerized di-thio-dinicotinic acid rings, with charge-balancing chloride ions and water mol-ecules between the layers. Hydrogen bonding between the chloride and water sites with the dimer appears to hold the structure together. Nearest neighbor nicotinic acid rings are offset when viewed down the axis, suggesting no added stability from ring stacking. The asymmetric unit corresponds to the empirical formula of the compound, and it packs with two formula units per unit cell.
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Date Issued: 2018-05-18
Identifier: FSU_pmch_29951238, 10.1107/S2056989018006916, PMC6002824, 29951238, 29951238, yk2114
Format: Citation

Title: Scaling Laws For Polymer Chains Grafted Onto Nanoparticles.
Creator: Yang, Guang, Kim, Kyoungmin, Wang, Wentao, Chen, Banghao, Mattoussi, Hedi, Hallinan, Daniel T.
Abstract/Description: An experimental approach is presented for identifying the scaling laws for polymer chains grafted onto gold nanoparticles. Poly(ethylene oxide) of various molecular weights are grafted onto gold nanoparticles via thiol end-functional groups. The polymer-grafted nanoparticles are self-assembled into monolayers from solvents of different quality. Over a significant range of graft densities, nanoparticle monolayers deposited from good (athermal) solvent exhibit particle spacing that scales...
Show moreAn experimental approach is presented for identifying the scaling laws for polymer chains grafted onto gold nanoparticles. Poly(ethylene oxide) of various molecular weights are grafted onto gold nanoparticles via thiol end-functional groups. The polymer-grafted nanoparticles are self-assembled into monolayers from solvents of different quality. Over a significant range of graft densities, nanoparticle monolayers deposited from good (athermal) solvent exhibit particle spacing that scales according to theoretical predictions for chains in dilute solution. This unexpected result for ordered nanoparticle monolayers is discussed in the context of the deposition process. In monolayers deposited from theta solvent, molecular weight scaling of particle spacing breaks down, possibly due to chain length dependence of solvent quality. In poor solvent, the structure of nanoparticle assemblies is not sufficiently ordered to obtain reliable measurements, possibly due to loss of nanoparticle dispersion. This approach opens up the possibility for accurate measurement of the effect of solvent on grafted chain scaling in nanoparticle assemblies.
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Date Issued: 2018-04-01
Identifier: FSU_libsubv1_wos_000430396100001, 10.1002/macp.201700417
Format: Citation

Title: Mechanistic Origins Of Enzyme Activation In Human Glucokinase Variants Associated With Congenital Hyperinsulinism.
Creator: Sternisha, Shawn M., Liu, Peilu, Marshall, Alan G., Miller, Brian G.
Abstract/Description: Human glucokinase (GCK) acts as the body's primary glucose sensor and plays a critical role in glucose homeostatic maintenance. Gain-of-function mutations in gck produce hyperactive enzyme variants that cause congenital hyperinsulinism. Prior biochemical and biophysical studies suggest that activated disease variants can be segregated into two mechanistically distinct classes, termed alpha-type and beta-type. Steady-state viscosity variation studies indicate that the k(cat), values of wild...
Show moreHuman glucokinase (GCK) acts as the body's primary glucose sensor and plays a critical role in glucose homeostatic maintenance. Gain-of-function mutations in gck produce hyperactive enzyme variants that cause congenital hyperinsulinism. Prior biochemical and biophysical studies suggest that activated disease variants can be segregated into two mechanistically distinct classes, termed alpha-type and beta-type. Steady-state viscosity variation studies indicate that the k(cat), values of wild-type GCK and an alpha-type variant are partially diffusion-limited, whereas the k(cat) value of a beta-type variant is viscosity-independent. Transient-state chemical quench-flow analyses demonstrate that wild-type GCK and the alpha-type variant display burst kinetics, whereas the beta-type variant lacks a burst phase. Comparative hydrogen-deuterium exchange mass spectrometry of unliganded enzymes demonstrates that a disordered active site loop, which folds upon binding of glucose, is protected from exchange in the alpha-type variant. The alpha-type variant also displays an increased level of exchange within a beta-strand located near the enzyme's hinge region, which becomes more solvent-exposed upon glucose binding. In contrast, beta-type activation causes no substantial difference in global or local exchange relative to that of unliganded, wild-type GCK. Together, these results demonstrate that alpha-type activation results from a shift in the conformational ensemble of unliganded GCK toward a state resembling the glucose-bound conformation, whereas beta-type activation is attributable to an accelerated rate of product release. This work elucidates the molecular basis of naturally occurring, activated GCK disease variants and provides insight into the structural and dynamic origins of GCK's unique kinetic cooperativity.
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Date Issued: 2018-03-13
Identifier: FSU_libsubv1_wos_000427661600011, 10.1021/acs.biochem.8b00022
Format: Citation

Title: Mechanistic Origins of Enzyme Activation in Human Glucokinase Variants Associated with Congenital Hyperinsulinism.
Creator: Sternisha, Shawn M, Liu, Peilu, Marshall, Alan G, Miller, Brian G
Abstract/Description: Human glucokinase (GCK) acts as the body's primary glucose sensor and plays a critical role in glucose homeostatic maintenance. Gain-of-function mutations in gck produce hyperactive enzyme variants that cause congenital hyperinsulinism. Prior biochemical and biophysical studies suggest that activated disease variants can be segregated into two mechanistically distinct classes, termed α-type and β-type. Steady-state viscosity variation studies indicate that the k values of wild-type GCK and an...
Show moreHuman glucokinase (GCK) acts as the body's primary glucose sensor and plays a critical role in glucose homeostatic maintenance. Gain-of-function mutations in gck produce hyperactive enzyme variants that cause congenital hyperinsulinism. Prior biochemical and biophysical studies suggest that activated disease variants can be segregated into two mechanistically distinct classes, termed α-type and β-type. Steady-state viscosity variation studies indicate that the k values of wild-type GCK and an α-type variant are partially diffusion-limited, whereas the k value of a β-type variant is viscosity-independent. Transient-state chemical quench-flow analyses demonstrate that wild-type GCK and the α-type variant display burst kinetics, whereas the β-type variant lacks a burst phase. Comparative hydrogen-deuterium exchange mass spectrometry of unliganded enzymes demonstrates that a disordered active site loop, which folds upon binding of glucose, is protected from exchange in the α-type variant. The α-type variant also displays an increased level of exchange within a β-strand located near the enzyme's hinge region, which becomes more solvent-exposed upon glucose binding. In contrast, β-type activation causes no substantial difference in global or local exchange relative to that of unliganded, wild-type GCK. Together, these results demonstrate that α-type activation results from a shift in the conformational ensemble of unliganded GCK toward a state resembling the glucose-bound conformation, whereas β-type activation is attributable to an accelerated rate of product release. This work elucidates the molecular basis of naturally occurring, activated GCK disease variants and provides insight into the structural and dynamic origins of GCK's unique kinetic cooperativity.
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Date Issued: 2018-03-13
Identifier: FSU_pmch_29425029, 10.1021/acs.biochem.8b00022, PMC5849571, 29425029, 29425029
Format: Citation

Title: Structural And Optical Properties Of Nanocrystalline Tio2 With Multiwalled Carbon Nanotubes And Its Photovoltaic Studies Using Ru(ii) Sensitizers.
Creator: Delekar, Sagar D., Dhodamani, Ananta G., More, Krantiveer V., Dongale, Tukaram D., Kamat, Rajanish K., Acquah, Steve F. A., Dalal, Naresh S., Panda, Dillip K.
Abstract/Description: In this study, the in situ sol-gel method has been deployed to prepare the titanium dioxide/multiwalled carbon nanotubes (TiO2/MWCNTs) nanocomposite (NCs) powders with varying content of MWCNTs (0.01-1.0 wt %), to construct the dye-sensitized solar cells (DSSCs). First, binder-free NCs were deposited on a transparent-conducting F:SnO2 (FTO) glass substrate by a doctor-blade technique and then anchored with Ru(II)-based dyes to either N719 or ruthenium phthalocyanine (RuPc). The structural and...
Show moreIn this study, the in situ sol-gel method has been deployed to prepare the titanium dioxide/multiwalled carbon nanotubes (TiO2/MWCNTs) nanocomposite (NCs) powders with varying content of MWCNTs (0.01-1.0 wt %), to construct the dye-sensitized solar cells (DSSCs). First, binder-free NCs were deposited on a transparent-conducting F:SnO2 (FTO) glass substrate by a doctor-blade technique and then anchored with Ru(II)-based dyes to either N719 or ruthenium phthalocyanine (RuPc). The structural and optical properties and interconnectivity of the materials within the composite are investigated thoroughly by various spectral techniques (XRD, XPS, Raman, FT-IR, and UV-vis), electron microscopy (HRTEM), and BET analysis. The experimental results suggest that the ratio of MWCNTs and TiO2 in NCs, morphology, and their interconnectivity influenced their structural, optical, and photovoltaic properties significantly. Finally, the photovoltaic performances of the assembled DSSCs with different content of MWCNTs to TiO2 films anchored with two different dyes were tested under one sun irradiation (100 mW/cm(2)). The measured current-voltage (IV) curve and incident photon-to-current conversion efficiency (IPCE) spectra of TiO2/0.1 wt % MWCNTs (T@0.1 C) for N719 dye show three times more power conversion efficiency (eta = 6.21%) which is opposed to an efficiency (eta = 2.07%) of T@0.1 C for RuPc dye under the same operating conditions.
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Date Issued: 2018-03
Identifier: FSU_libsubv1_wos_000427939400031, 10.1021/acsomega.7b01316
Format: Citation

Title: The repeat region of cortactin is intrinsically disordered in solution.
Creator: Li, Xiaofeng, Tao, Yeqing, Murphy, James W, Scherer, Alexander N, Lam, TuKiet T, Marshall, Alan G, Koleske, Anthony J, Boggon, Titus J
Abstract/Description: The multi-domain protein, cortactin, contains a 37-residue repeating motif that binds to actin filaments. This cortactin repeat region comprises 6½ similar copies of the motif and binds actin filaments. To better understand this region of cortactin, and its fold, we conducted extensive biophysical analysis. Size exclusion chromatography with multi-angle light scattering (SEC-MALS) reveals that neither constructs of the cortactin repeats alone or together with the adjacent helical region homo...
Show moreThe multi-domain protein, cortactin, contains a 37-residue repeating motif that binds to actin filaments. This cortactin repeat region comprises 6½ similar copies of the motif and binds actin filaments. To better understand this region of cortactin, and its fold, we conducted extensive biophysical analysis. Size exclusion chromatography with multi-angle light scattering (SEC-MALS) reveals that neither constructs of the cortactin repeats alone or together with the adjacent helical region homo-oligomerize. Using circular dichroism (CD) we find that in solution the cortactin repeats resemble a coil-like intrinsically disordered protein. Small-angle X-ray scattering (SAXS) also indicates that the cortactin repeats are intrinsically unfolded, and the experimentally observed radius of gyration (R ) is coincidental to that calculated by the program Flexible-Meccano for an unfolded peptide of this length. Finally, hydrogen-deuterium exchange mass spectrometry (HDX-MS) indicates that the domain contains limited hydrophobic core regions. These experiments therefore provide evidence that in solution the cortactin repeat region of cortactin is intrinsically disordered.
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Date Issued: 2017-12-01
Identifier: FSU_pmch_29196701, 10.1038/s41598-017-16959-1, PMC5711941, 29196701, 29196701, 10.1038/s41598-017-16959-1
Format: Citation

Title: Bulk assembly of organic metal halide nanotubes.
Creator: Lin, Haoran, Zhou, Chenkun, Tian, Yu, Besara, Tiglet, Neu, Jennifer, Siegrist, Theo, Zhou, Yan, Bullock, James, Schanze, Kirk S, Ming, Wenmei, Du, Mao-Hua, Ma, Biwu
Abstract/Description: The organic metal halide hybrids welcome a new member with a one-dimensional (1D) tubular structure. Herein we report the synthesis and characterization of a single crystalline bulk assembly of organic metal halide nanotubes, (CHN)PbBr. In a metal halide nanotube, six face-sharing metal halide dimers (PbBr) connect at the corners to form rings that extend in one dimension, of which the inside and outside surfaces are coated with protonated hexamethylenetetramine (HMTA) cations (CHN). This...
Show moreThe organic metal halide hybrids welcome a new member with a one-dimensional (1D) tubular structure. Herein we report the synthesis and characterization of a single crystalline bulk assembly of organic metal halide nanotubes, (CHN)PbBr. In a metal halide nanotube, six face-sharing metal halide dimers (PbBr) connect at the corners to form rings that extend in one dimension, of which the inside and outside surfaces are coated with protonated hexamethylenetetramine (HMTA) cations (CHN). This unique 1D tubular structure possesses highly localized electronic states with strong quantum confinement, resulting in the formation of self-trapped excitons that give strongly Stokes shifted broadband yellowish-white emission with a photoluminescence quantum efficiency (PLQE) of ∼7%. Having realized single crystalline bulk assemblies of two-dimensional (2D) wells, 1D wires, and now 1D tubes using organic metal halide hybrids, our work significantly advances the research on bulk assemblies of quantum-confined materials.
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Date Issued: 2017-12-01
Identifier: FSU_pmch_29619186, 10.1039/c7sc03675b, PMC5862099, 29619186, 29619186, c7sc03675b
Format: Citation

Title: Luminescent zero-dimensional organic metal halide hybrids with near-unity quantum efficiency.
Creator: Zhou, Chenkun, Lin, Haoran, Tian, Yu, Yuan, Zhao, Clark, Ronald, Chen, Banghao, van de Burgt, Lambertus J, Wang, Jamie C, Zhou, Yan, Hanson, Kenneth, Meisner, Quinton J, Neu,...
Show moreZhou, Chenkun, Lin, Haoran, Tian, Yu, Yuan, Zhao, Clark, Ronald, Chen, Banghao, van de Burgt, Lambertus J, Wang, Jamie C, Zhou, Yan, Hanson, Kenneth, Meisner, Quinton J, Neu, Jennifer, Besara, Tiglet, Siegrist, Theo, Lambers, Eric, Djurovich, Peter, Ma, Biwu
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Abstract/Description: Single crystalline zero-dimensional (0D) organic-inorganic hybrid materials with perfect host-guest structures have been developed as a new generation of highly efficient light emitters. Here we report a series of lead-free organic metal halide hybrids with a 0D structure, (CNHX)SnX (X = Br, I) and (CNH)SbX (X = Cl), in which the individual metal halide octahedra (SnX) and quadrangular pyramids (SbX) are completely isolated from each other and surrounded by the organic ligands CNHX and CNH,...
Show moreSingle crystalline zero-dimensional (0D) organic-inorganic hybrid materials with perfect host-guest structures have been developed as a new generation of highly efficient light emitters. Here we report a series of lead-free organic metal halide hybrids with a 0D structure, (CNHX)SnX (X = Br, I) and (CNH)SbX (X = Cl), in which the individual metal halide octahedra (SnX) and quadrangular pyramids (SbX) are completely isolated from each other and surrounded by the organic ligands CNHX and CNH, respectively. The isolation of the photoactive metal halide species by the wide band gap organic ligands leads to no interaction or electronic band formation between the metal halide species, allowing the bulk materials to exhibit the intrinsic properties of the individual metal halide species. These 0D organic metal halide hybrids can also be considered as perfect host-guest systems, with the metal halide species periodically doped in the wide band gap matrix. Highly luminescent, strongly Stokes shifted broadband emissions with photoluminescence quantum efficiencies (PLQEs) of close to unity were realized, as a result of excited state structural reorganization of the individual metal halide species. Our discovery of highly luminescent single crystalline 0D organic-inorganic hybrid materials as perfect host-guest systems opens up a new paradigm in functional materials design.
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Date Issued: 2017-11-21
Identifier: FSU_pmch_29629122, 10.1039/c7sc04539e, PMC5870054, 29629122, 29629122, c7sc04539e
Format: Citation

Title: Erratum: Organocatalyzed synthesis of fluorinated poly(aryl thioethers)..
Creator: Park, Nathaniel H, Gomes, Gabriel Dos Passos, Fevre, Mareva, Jones, Gavin O, Alabugin, Igor V, Hedrick, James L
Abstract/Description: A correction to this article has been published and is linked from the HTML version of this article.
Date Issued: 2017-11-13
Identifier: FSU_pmch_29133869, 10.1038/s41467-017-01129-8, PMC5684191, 29133869, 29133869, 10.1038/s41467-017-01129-8
Format: Citation

Title: A mesoporous cationic thorium-organic framework that rapidly traps anionic persistent organic pollutants.
Creator: Li, Yuxiang, Yang, Zaixing, Wang, Yanlong, Bai, Zhuanling, Zheng, Tao, Dai, Xing, Liu, Shengtang, Gui, Daxiang, Liu, Wei, Chen, Meng, Chen, Lanhua, Diwu, Juan, Zhu, Lingyan,...
Show moreLi, Yuxiang, Yang, Zaixing, Wang, Yanlong, Bai, Zhuanling, Zheng, Tao, Dai, Xing, Liu, Shengtang, Gui, Daxiang, Liu, Wei, Chen, Meng, Chen, Lanhua, Diwu, Juan, Zhu, Lingyan, Zhou, Ruhong, Chai, Zhifang, Albrecht-Schmitt, Thomas E, Wang, Shuao
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Abstract/Description: Many environmental pollutants inherently exist in their anionic forms and are therefore highly mobile in natural water systems. Cationic framework materials that can capture those pollutants are highly desirable but scarcely reported. Here we present a mesoporous cationic thorium-based MOF (SCU-8) containing channels with a large inner diameter of 2.2 nm and possessing a high surface area of 1360 m g. The anion-exchange properties of SCU-8 were explored with many anions including small oxo...
Show moreMany environmental pollutants inherently exist in their anionic forms and are therefore highly mobile in natural water systems. Cationic framework materials that can capture those pollutants are highly desirable but scarcely reported. Here we present a mesoporous cationic thorium-based MOF (SCU-8) containing channels with a large inner diameter of 2.2 nm and possessing a high surface area of 1360 m g. The anion-exchange properties of SCU-8 were explored with many anions including small oxo anions like ReO and CrO as well as anionic organic dyes like methyl blue and the persistent organic pollutant, perfluorooctane sulfonate (PFOS). Both fast uptake kinetics and great sorption selectivity toward PFOS are observed. The underlying sorption mechanism was probed using quantum mechanical and molecular dynamics simulations. These computational results reveal that PFOS anions are immobilized in SCU-8 by driving forces including electrostatic interactions, hydrogen bonds, hydrophobic interactions, and van der Waals interactions at different adsorption stages.
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Date Issued: 2017-11-07
Identifier: FSU_pmch_29116079, 10.1038/s41467-017-01208-w, PMC5677036, 29116079, 29116079, 10.1038/s41467-017-01208-w
Format: Citation

Title: NMR spectroscopy up to 35.2T using a series-connected hybrid magnet.
Creator: Gan, Zhehong, Hung, Ivan, Wang, Xiaoling, Paulino, Joana, Wu, Gang, Litvak, Ilya M, Gor'kov, Peter L, Brey, William W, Lendi, Pietro, Schiano, Jeffrey L, Bird, Mark D, Dixon,...
Show moreGan, Zhehong, Hung, Ivan, Wang, Xiaoling, Paulino, Joana, Wu, Gang, Litvak, Ilya M, Gor'kov, Peter L, Brey, William W, Lendi, Pietro, Schiano, Jeffrey L, Bird, Mark D, Dixon, Iain R, Toth, Jack, Boebinger, Gregory S, Cross, Timothy A
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Abstract/Description: The National High Magnetic Field Laboratory has brought to field a Series-Connected Hybrid magnet for NMR spectroscopy. As a DC powered magnet it can be operated at fields up to 36.1T. The series connection between a superconducting outsert and a resistive insert dramatically minimizes the high frequency fluctuations of the magnetic field typically observed in purely resistive magnets. Current-density-grading among various resistive coils was used for improved field homogeneity. The 48mm...
Show moreThe National High Magnetic Field Laboratory has brought to field a Series-Connected Hybrid magnet for NMR spectroscopy. As a DC powered magnet it can be operated at fields up to 36.1T. The series connection between a superconducting outsert and a resistive insert dramatically minimizes the high frequency fluctuations of the magnetic field typically observed in purely resistive magnets. Current-density-grading among various resistive coils was used for improved field homogeneity. The 48mm magnet bore and 42mm outer diameter of the probes leaves limited space for conventional shims and consequently a combination of resistive and ferromagnetic shims are used. Field maps corrected for field instabilities were obtained and shimming achieved better than 1ppm homogeneity over a cylindrical volume of 1cm diameter and height. The magnetic field is regulated within 0.2ppm using an external Li lock sample doped with paramagnetic MnCl. The improved field homogeneity and field regulation using a modified AVANCE NEO console enables NMR spectroscopy at H frequencies of 1.0, 1.2 and 1.5GHz. NMR at 1.5GHz reflects a 50% increase in field strength above the highest superconducting magnets currently available. Three NMR probes have been constructed each equipped with an external lock rf coil for field regulation. Initial NMR results obtained from the SCH magnet using these probes illustrate the very exciting potential of ultra-high magnetic fields.
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Date Issued: 2017-11-01
Identifier: FSU_pmch_28890288, 10.1016/j.jmr.2017.08.007, PMC5675800, 28890288, 28890288, S1090-7807(17)30204-5
Format: Citation

Title: Transformation of doped graphite into cluster-encapsulated fullerene cages.
Creator: Mulet-Gas, Marc, Abella, Laura, Cerón, Maira R, Castro, Edison, Marshall, Alan G, Rodríguez-Fortea, Antonio, Echegoyen, Luis, Poblet, Josep M, Dunk, Paul W
Abstract/Description: An ultimate goal in carbon nanoscience is to decipher formation mechanisms of highly ordered systems. Here, we disclose chemical processes that result in formation of high-symmetry clusterfullerenes, which attract interest for use in applications that span biomedicine to molecular electronics. The conversion of doped graphite into a C cage is shown to occur through bottom-up self-assembly reactions. Unlike conventional forms of fullerene, the iconic Buckminsterfullerene cage, I -C, is...
Show moreAn ultimate goal in carbon nanoscience is to decipher formation mechanisms of highly ordered systems. Here, we disclose chemical processes that result in formation of high-symmetry clusterfullerenes, which attract interest for use in applications that span biomedicine to molecular electronics. The conversion of doped graphite into a C cage is shown to occur through bottom-up self-assembly reactions. Unlike conventional forms of fullerene, the iconic Buckminsterfullerene cage, I -C, is entirely avoided in the bottom-up formation mechanism to afford synthesis of group 3-based metallic nitride clusterfullerenes. The effects of structural motifs and cluster-cage interactions on formation of compounds in the solvent-extractable C-C region are determined by in situ studies of defined clusterfullerenes under typical synthetic conditions. This work establishes the molecular origin and mechanism that underlie formation of unique carbon cage materials, which may be used as a benchmark to guide future nanocarbon explorations.
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Date Issued: 2017-10-31
Identifier: FSU_pmch_29089497, 10.1038/s41467-017-01295-9, PMC5663703, 29089497, 29089497, 10.1038/s41467-017-01295-9
Format: Citation

Title: Accurate Identification of Unknown and Known Metabolic Mixture Components by Combining 3D NMR with Fourier Transform Ion Cyclotron Resonance Tandem Mass Spectrometry.
Creator: Wang, Cheng, He, Lidong, Li, Da-Wei, Bruschweiler-Li, Lei, Marshall, Alan G, Brüschweiler, Rafael
Abstract/Description: Metabolite identification in metabolomics samples is a key step that critically impacts downstream analysis. We recently introduced the SUMMIT NMR/mass spectrometry (MS) hybrid approach for the identification of the molecular structure of unknown metabolites based on the combination of NMR, MS, and combinatorial cheminformatics. Here, we demonstrate the feasibility of the approach for an untargeted analysis of both a model mixture and E. coli cell lysate based on 2D/3D NMR experiments in...
Show moreMetabolite identification in metabolomics samples is a key step that critically impacts downstream analysis. We recently introduced the SUMMIT NMR/mass spectrometry (MS) hybrid approach for the identification of the molecular structure of unknown metabolites based on the combination of NMR, MS, and combinatorial cheminformatics. Here, we demonstrate the feasibility of the approach for an untargeted analysis of both a model mixture and E. coli cell lysate based on 2D/3D NMR experiments in combination with Fourier transform ion cyclotron resonance MS and MS/MS data. For 19 of the 25 model metabolites, SUMMIT yielded complete structures that matched those in the mixture independent of database information. Of those, seven top-ranked structures matched those in the mixture, and four of those were further validated by positive ion MS/MS. For five metabolites, not part of the 19 metabolites, correct molecular structural motifs could be identified. For E. coli, SUMMIT MS/NMR identified 20 previously known metabolites with three or more H spins independent of database information. Moreover, for 15 unknown metabolites, molecular structural fragments were determined consistent with their spin systems and chemical shifts. By providing structural information for entire metabolites or molecular fragments, SUMMIT MS/NMR greatly assists the targeted or untargeted analysis of complex mixtures of unknown compounds.
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Date Issued: 2017-10-06
Identifier: FSU_pmch_28795575, 10.1021/acs.jproteome.7b00457, PMC5663437, 28795575, 28795575
Format: Citation

Title: Diffusion of Sites versus Polymers in Polyelectrolyte Complexes and Multilayers.
Creator: Fares, Hadi, Schlenoff, Joseph
Abstract/Description: It has long been assumed that the spontaneous formation of materials such as complexes and multilayers from charged polymers depends on (inter)diffusion of these polyelectrolytes. Here, we separately examine the mass transport of polymer molecules and extrinsic sites—charged polyelectrolyte repeat units balanced by counterions—within thin films of polyelectrolyte complex, PEC, using sensitive isotopic labeling techniques. The apparent diffusion coefficients of these sites within PEC films of...
Show moreIt has long been assumed that the spontaneous formation of materials such as complexes and multilayers from charged polymers depends on (inter)diffusion of these polyelectrolytes. Here, we separately examine the mass transport of polymer molecules and extrinsic sites—charged polyelectrolyte repeat units balanced by counterions—within thin films of polyelectrolyte complex, PEC, using sensitive isotopic labeling techniques. The apparent diffusion coefficients of these sites within PEC films of poly(diallyldimethylammonium), PDADMA, and poly(styrenesulfonate), PSS, are at least 2 orders of magnitude faster than the diffusion of polyelectrolytes themselves. This is because site diffusion requires only local rearrangements of polyelectrolyte repeat units, placing far fewer kinetic limitations on the assembly of polyelectrolyte complexes in all of their forms. Site diffusion strongly depends on the salt concentration (ionic strength) of the environment, and diffusion of PDADMA sites is faster than that of PSS sites, accounting for the asymmetric nature of multilayer growth. Site diffusion is responsible for multilayer growth in the linear and into the exponential regimes, which explains how PDADMA can mysteriously “pass through” layers of PSS. Using quantitative relationships between site diffusion coefficient and salt concentration, conditions were identified that allowed the diffusion length to always exceed the film thickness, leading to full exponential growth over 3 orders of magnitude thickness. Both site and polymer diffusion were independent of molecular weight, suggesting that ion pairing density is a limiting factor. Polyelectrolyte complexes are examples of a broader class of dynamic bulk polymeric materials that (self-) assemble via the transport of cross-links or defects rather than actual molecules.
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Date Issued: 2017-10-05
Identifier: FSU_libsubv1_scholarship_submission_1543269470_f050f9b2, 10.1021/jacs.7b07905
Format: Citation

Title: Water and the Glass Transition Temperature in a Polyelectrolyte Complex.
Creator: Fu, Jingcheng, Abbett, Rachel L., Fares, Hadi M., Schlenoff, Joseph B.
Abstract/Description: Hydrated polyelectrolyte complexes, H-PECs, have recently started attracting renewed interest as a class of highly solvated/plasticized blends. H-PECs are observed to undergo a transition in mechanical properties close to room temperature. Whether this is a true glass transition has been questioned recently: the material has an unusually low modulus in the “glassy” state and molecular dynamics simulations have suggested temperature-induced dehydration and water structure changes are...
Show moreHydrated polyelectrolyte complexes, H-PECs, have recently started attracting renewed interest as a class of highly solvated/plasticized blends. H-PECs are observed to undergo a transition in mechanical properties close to room temperature. Whether this is a true glass transition has been questioned recently: the material has an unusually low modulus in the “glassy” state and molecular dynamics simulations have suggested temperature-induced dehydration and water structure changes are responsible for the transition. Using in situ infrared spectroscopic methods on thin films of a widely-studied H-PEC we find no definitive evidence for changes in the hydration state of functional groups, the water content, or water structure below or above Tg for stoichiometric and nonstoichiometric H-PECs. These complexes represent a promising platform for fundamental studies of the glass transition, since the coupling between chains can be modified by “doping” the material with salt, which breaks ion pairing crosslinks. The Fox equation was used to estimate Tg’s for paired and unpaired oppositely-charged repeat units.
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Date Issued: 2017-09-22
Identifier: FSU_libsubv1_scholarship_submission_1540241093_22e4df52, 10.1021/acsmacrolett.7b00668
Format: Citation

Title: Front-End Electron Transfer Dissociation Coupled to a 21 Tesla FT-ICR Mass Spectrometer for Intact Protein Sequence Analysis.
Creator: Weisbrod, Chad R, Kaiser, Nathan K, Syka, John E P, Early, Lee, Mullen, Christopher, Dunyach, Jean-Jacques, English, A Michelle, Anderson, Lissa C, Blakney, Greg T, Shabanowitz,...
Show moreWeisbrod, Chad R, Kaiser, Nathan K, Syka, John E P, Early, Lee, Mullen, Christopher, Dunyach, Jean-Jacques, English, A Michelle, Anderson, Lissa C, Blakney, Greg T, Shabanowitz, Jeffrey, Hendrickson, Christopher L, Marshall, Alan G, Hunt, Donald F
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Abstract/Description: High resolution mass spectrometry is a key technology for in-depth protein characterization. High-field Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) enables high-level interrogation of intact proteins in the most detail to date. However, an appropriate complement of fragmentation technologies must be paired with FTMS to provide comprehensive sequence coverage, as well as characterization of sequence variants, and post-translational modifications. Here we describe...
Show moreHigh resolution mass spectrometry is a key technology for in-depth protein characterization. High-field Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) enables high-level interrogation of intact proteins in the most detail to date. However, an appropriate complement of fragmentation technologies must be paired with FTMS to provide comprehensive sequence coverage, as well as characterization of sequence variants, and post-translational modifications. Here we describe the integration of front-end electron transfer dissociation (FETD) with a custom-built 21 tesla FT-ICR mass spectrometer, which yields unprecedented sequence coverage for proteins ranging from 2.8 to 29 kDa, without the need for extensive spectral averaging (e.g., ~60% sequence coverage for apo-myoglobin with four averaged acquisitions). The system is equipped with a multipole storage device separate from the ETD reaction device, which allows accumulation of multiple ETD fragment ion fills. Consequently, an optimally large product ion population is accumulated prior to transfer to the ICR cell for mass analysis, which improves mass spectral signal-to-noise ratio, dynamic range, and scan rate. We find a linear relationship between protein molecular weight and minimum number of ETD reaction fills to achieve optimum sequence coverage, thereby enabling more efficient use of instrument data acquisition time. Finally, real-time scaling of the number of ETD reactions fills during method-based acquisition is shown, and the implications for LC-MS/MS top-down analysis are discussed. Graphical Abstract ᅟ.
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Date Issued: 2017-09-01
Identifier: FSU_pmch_28721671, 10.1007/s13361-017-1702-3, PMC5711562, 28721671, 28721671, 10.1007/s13361-017-1702-3
Format: Citation

Title: Best practices for managing large CryoEM facilities.
Creator: Alewijnse, Bart, Ashton, Alun W, Chambers, Melissa G, Chen, Songye, Cheng, Anchi, Ebrahim, Mark, Eng, Edward T, Hagen, Wim J H, Koster, Abraham J, López, Claudia S, Lukoyanova,...
Show moreAlewijnse, Bart, Ashton, Alun W, Chambers, Melissa G, Chen, Songye, Cheng, Anchi, Ebrahim, Mark, Eng, Edward T, Hagen, Wim J H, Koster, Abraham J, López, Claudia S, Lukoyanova, Natalya, Ortega, Joaquin, Renault, Ludovic, Reyntjens, Steve, Rice, William J, Scapin, Giovanna, Schrijver, Raymond, Siebert, Alistair, Stagg, Scott M, Grum-Tokars, Valerie, Wright, Elizabeth R, Wu, Shenping, Yu, Zhiheng, Zhou, Z Hong, Carragher, Bridget, Potter, Clinton S
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Abstract/Description: This paper provides an overview of the discussion and presentations from the Workshop on the Management of Large CryoEM Facilities held at the New York Structural Biology Center, New York, NY on February 6-7, 2017. A major objective of the workshop was to discuss best practices for managing cryoEM facilities. The discussions were largely focused on supporting single-particle methods for cryoEM and topics included: user access, assessing projects, workflow, sample handling, microscopy, data...
Show moreThis paper provides an overview of the discussion and presentations from the Workshop on the Management of Large CryoEM Facilities held at the New York Structural Biology Center, New York, NY on February 6-7, 2017. A major objective of the workshop was to discuss best practices for managing cryoEM facilities. The discussions were largely focused on supporting single-particle methods for cryoEM and topics included: user access, assessing projects, workflow, sample handling, microscopy, data management and processing, and user training.
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Date Issued: 2017-09-01
Identifier: FSU_pmch_28827185, 10.1016/j.jsb.2017.07.011, PMC5605453, 28827185, 28827185, S1047-8477(17)30131-4
Format: Citation

Title: Mapping the contact surfaces in the Lamin A:AIMP3 complex by hydrogen/deuterium exchange FT-ICR mass spectrometry.
Creator: Tao, Yeqing, Fang, Pengfei, Kim, Sunghoon, Guo, Min, Young, Nicolas L, Marshall, Alan G
Abstract/Description: Aminoacyl-tRNA synthetases-interacting multifunctional protein3 (AIMP3/p18) is involved in the macromolecular tRNA synthetase complex via its interaction with several aminoacyl-tRNA synthetases. Recent reports reveal a novel function of AIMP3 as a tumor suppressor by accelerating cellular senescence and causing defects in nuclear morphology. AIMP3 specifically mediates degradation of mature Lamin A (LmnA), a major component of the nuclear envelope matrix; however, the mechanism of how AIMP3...
Show moreAminoacyl-tRNA synthetases-interacting multifunctional protein3 (AIMP3/p18) is involved in the macromolecular tRNA synthetase complex via its interaction with several aminoacyl-tRNA synthetases. Recent reports reveal a novel function of AIMP3 as a tumor suppressor by accelerating cellular senescence and causing defects in nuclear morphology. AIMP3 specifically mediates degradation of mature Lamin A (LmnA), a major component of the nuclear envelope matrix; however, the mechanism of how AIMP3 interacts with LmnA is unclear. Here we report solution-phase hydrogen/deuterium exchange (HDX) for AIMP3, LmnA, and AIMP3 in association with the LmnA C-terminus. Reversed-phase LC coupled with LTQ 14.5 T Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) results in high mass accuracy and resolving power for comparing the D-uptake profiles for AIMP3, LmnA, and their complex. The results show that the AIMP3-LmnA interaction involves one of the two putative binding sites and an adjacent novel interface on AIMP3. LmnA binds AIMP3 via its extreme C-terminus. Together these findings provide a structural insight for understanding the interaction between AIMP3 and LmnA in AIMP3 degradation.
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Date Issued: 2017-08-10
Identifier: FSU_pmch_28797100, 10.1371/journal.pone.0181869, PMC5552228, 28797100, 28797100, PONE-D-17-10096
Format: Citation

Title: DNA mismatch repair protein Mlh1 is required for tetravalent chromium intermediate-induced DNA damage.
Creator: Wakeman, Timothy P, Yang, Aimin, Dalal, Naresh S, Boohaker, Rebecca J, Zeng, Qinghua, Ding, Qiang, Xu, Bo
Abstract/Description: Hexavalent chromium (Cr[VI]) is associated with occupational lung cancer and poses a significant public health concern. When exposed to Cr[VI], cells rapidly internalize this compound and metabolize it to Cr[III]. Byproducts of Cr[VI] metabolism include unstable Cr[V] and Cr[IV] intermediates that are believed to be directly responsible for the genotoxicity and carcinogenicity caused by Cr[VI] exposure; however, the carcinogenic potential of the Cr intermediates and the mechanisms of Cr...
Show moreHexavalent chromium (Cr[VI]) is associated with occupational lung cancer and poses a significant public health concern. When exposed to Cr[VI], cells rapidly internalize this compound and metabolize it to Cr[III]. Byproducts of Cr[VI] metabolism include unstable Cr[V] and Cr[IV] intermediates that are believed to be directly responsible for the genotoxicity and carcinogenicity caused by Cr[VI] exposure; however, the carcinogenic potential of the Cr intermediates and the mechanisms of Cr-induced carcinogenesis remain to be further defined. Utilizing synthetic Cr[IV] and Cr[V] compounds, we demonstrate here that Cr[IV] or Cr[V] exposure induces DNA double-strand breaks; however, of the two compounds, mammalian cells only respond to Cr[V]-induced DNA damage. Exposure to Cr[V], but not Cr[IV], results in initiation of cell cycle checkpoints and activates the ATM kinase, a critical regulator of the DNA damage response. Furthermore, cells exposed to Cr[IV] have significantly increased mutation frequencies in the HPRT gene compared to cells exposed to Cr[V], indicating that Cr[IV] possesses a higher mutagenic potential than Cr[V]. We also find that MLH1, a critical mismatch repair (MMR) protein, is required for activation of the G2/M cell cycle checkpoint in response to Cr[VI] exposure and to limit Cr-induced mutagenesis. Our results provide evidence for Cr[IV] as the ultimate mutagenic intermediate produced during Cr[VI] metabolism and indicate that functional MMR is crucial in the cellular response to chromium exposure.
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Date Issued: 2017-08-10
Identifier: FSU_pmch_29137397, 10.18632/oncotarget.20150, PMC5663569, 29137397, 29137397, 20150
Format: Citation

Title: Organocatalyzed synthesis of fluorinated poly(aryl thioethers).
Creator: Park, Nathaniel H, Gomes, Gabriel Dos Passos, Fevre, Mareva, Jones, Gavin O, Alabugin, Igor V, Hedrick, James L
Abstract/Description: The preparation of high-performance fluorinated poly(aryl thioethers) has received little attention compared to the corresponding poly(aryl ethers), despite the excellent physical properties displayed by many polysulfides. Herein, we report a highly efficient route to fluorinated poly(aryl thioethers) via an organocatalyzed nucleophilic aromatic substitution of silyl-protected dithiols. This approach requires low catalyst loadings, proceeds rapidly at room temperature, and is effective for...
Show moreThe preparation of high-performance fluorinated poly(aryl thioethers) has received little attention compared to the corresponding poly(aryl ethers), despite the excellent physical properties displayed by many polysulfides. Herein, we report a highly efficient route to fluorinated poly(aryl thioethers) via an organocatalyzed nucleophilic aromatic substitution of silyl-protected dithiols. This approach requires low catalyst loadings, proceeds rapidly at room temperature, and is effective for many different perfluorinated or highly activated aryl monomers. Computational investigations of the reaction mechanism reveal an unexpected, concerted SAr mechanism, with the organocatalyst playing a critical, dual-activation role in facilitating the process. Not only does this remarkable reactivity enable rapid access to fluorinated poly(aryl thioethers), but also opens new avenues for the processing, fabrication, and functionalization of fluorinated materials with easy removal of the volatile catalyst and TMSF byproducts.Fluorinated poly(aryl thioethers), unlike their poly(aryl ethers) counterparts, have received little attention despite excellent physical properties displayed by many polysulfides. Here the authors show a highly efficient route to fluorinated poly(aryl thioethers) via an organocatalyzed nucleophilic aromatic substitution of silyl-protected dithiols.
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Date Issued: 2017-08-01
Identifier: FSU_pmch_28761127, 10.1038/s41467-017-00186-3, PMC5537313, 28761127, 28761127, 10.1038/s41467-017-00186-3
Format: Citation

Title: Chemical reaction within a compact non-porous crystal containing molecular clusters without the loss of crystallinity.
Creator: Zhang, Ming, Yang, Tao, Wang, Zhenxing, Ma, Xiong-Feng, Zhang, Yuexing, Greer, Samuel M, Stoian, Sebastian A, Ouyang, Zhong-Wen, Nojiri, Hiroyuki, Kurmoo, Mohamedally, Zeng,...
Show moreZhang, Ming, Yang, Tao, Wang, Zhenxing, Ma, Xiong-Feng, Zhang, Yuexing, Greer, Samuel M, Stoian, Sebastian A, Ouyang, Zhong-Wen, Nojiri, Hiroyuki, Kurmoo, Mohamedally, Zeng, Ming-Hua
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Abstract/Description: The very rare occurrence of a gas-solid chemical reaction has been found to take place on a molecule within a compact non-porous crystal without destroying its long-range structural order and retaining similar crystal structures when yellow crystals of FeII4()Cl(MeOH) were exposed to air to give black [FeIII4()Cl(OH)]·2HO. The latter cannot be synthesised directly. The original cluster underwent an exchange of methanol to hydroxide, an oxidation of Fe(ii) to Fe(iii), a change in...
Show moreThe very rare occurrence of a gas-solid chemical reaction has been found to take place on a molecule within a compact non-porous crystal without destroying its long-range structural order and retaining similar crystal structures when yellow crystals of FeII4()Cl(MeOH) were exposed to air to give black [FeIII4()Cl(OH)]·2HO. The latter cannot be synthesised directly. The original cluster underwent an exchange of methanol to hydroxide, an oxidation of Fe(ii) to Fe(iii), a change in stereochemistry and hydration while the packing and space-group remained unaltered.
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Date Issued: 2017-08-01
Identifier: FSU_pmch_28970914, 10.1039/c7sc01041a, PMC5609145, 28970914, 28970914, c7sc01041a
Format: Citation

Title: Proteomic Characterization Of Paired Non-malignant And Malignant African-american Prostate Epithelial Cell Lines Distinguishes Them By Structural Proteins.
Creator: Myers, Jennifer S., Vallega, Karin A., White, Jason, Yu, Kaixian, Yates, Clayton C., Sang, Qing-Xiang Amy
Abstract/Description: Background: While many factors may contribute to the higher prostate cancer incidence and mortality experienced by African-American men compared to their counterparts, the contribution of tumor biology is underexplored due to inadequate availability of African-American patient-derived cell lines and specimens. Here, we characterize the proteomes of non-malignant RC-77 N/E and malignant RC-77 T/E prostate epithelial cell lines previously established from prostate specimens from the same...
Show moreBackground: While many factors may contribute to the higher prostate cancer incidence and mortality experienced by African-American men compared to their counterparts, the contribution of tumor biology is underexplored due to inadequate availability of African-American patient-derived cell lines and specimens. Here, we characterize the proteomes of non-malignant RC-77 N/E and malignant RC-77 T/E prostate epithelial cell lines previously established from prostate specimens from the same African-American patient with early stage primary prostate cancer. Methods: In this comparative proteomic analysis of RC-77 N/E and RC-77 T/E cells, differentially expressed proteins were identified and analyzed for overrepresentation of PANTHER protein classes, Gene Ontology annotations, and pathways. The enrichment of gene sets and pathway significance were assessed using Gene Set Enrichment Analysis and Signaling Pathway Impact Analysis, respectively. The gene and protein expression data of age- and stage-matched prostate cancer specimens from The Cancer Genome Atlas were analyzed. Results: Structural and cytoskeletal proteins were differentially expressed and statistically overrepresented between RC-77 N/E and RC-77 T/E cells. Beta-catenin, alpha-actinin-1, and filamin-A were upregulated in the tumorigenic RC-77 T/E cells, while integrin beta-1, integrin alpha-6, caveolin-1, laminin subunit gamma-2, and CD44 antigen were downregulated. The increased protein level of beta-catenin and the reduction of caveolin-1 protein level in the tumorigenic RC-77 T/E cells mirrored the upregulation of beta-catenin mRNA and downregulation of caveolin-1 mRNA in African-American prostate cancer specimens compared to non-malignant controls. After subtracting race-specific non-malignant RNA expression, beta-catenin and caveolin-1 mRNA expression levels were higher in African-American prostate cancer specimens than in Caucasian-American specimens. The "ECM-Receptor Interaction" and "Cell Adhesion Molecules", and the "Tight Junction" and "Adherens Junction" pathways contained proteins are associated with RC-77 N/E and RC-77 T/E cells, respectively. Conclusions: Our results suggest RC-77 T/E and RC-77 N/E cell lines can be distinguished by differentially expressed structural and cytoskeletal proteins, which appeared in several pathways across multiple analyses. Our results indicate that the expression of beta-catenin and caveolin-1 may be prostate cancer- and race-specific. Although the RC-77 cell model may not be representative of all African-American prostate cancer due to tumor heterogeneity, it is a unique resource for studying prostate cancer initiation and progression.
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Date Issued: 2017-07-11
Identifier: FSU_libsubv1_wos_000405352400004, 10.1186/s12885-017-3462-7
Format: Citation

Title: Proteomic characterization of paired non-malignant and malignant African-American prostate epithelial cell lines distinguishes them by structural proteins.
Creator: Myers, Jennifer S, Vallega, Karin A, White, Jason, Yu, Kaixian, Yates, Clayton C, Sang, Qing-Xiang Amy
Abstract/Description: While many factors may contribute to the higher prostate cancer incidence and mortality experienced by African-American men compared to their counterparts, the contribution of tumor biology is underexplored due to inadequate availability of African-American patient-derived cell lines and specimens. Here, we characterize the proteomes of non-malignant RC-77 N/E and malignant RC-77 T/E prostate epithelial cell lines previously established from prostate specimens from the same African-American...
Show moreWhile many factors may contribute to the higher prostate cancer incidence and mortality experienced by African-American men compared to their counterparts, the contribution of tumor biology is underexplored due to inadequate availability of African-American patient-derived cell lines and specimens. Here, we characterize the proteomes of non-malignant RC-77 N/E and malignant RC-77 T/E prostate epithelial cell lines previously established from prostate specimens from the same African-American patient with early stage primary prostate cancer. In this comparative proteomic analysis of RC-77 N/E and RC-77 T/E cells, differentially expressed proteins were identified and analyzed for overrepresentation of PANTHER protein classes, Gene Ontology annotations, and pathways. The enrichment of gene sets and pathway significance were assessed using Gene Set Enrichment Analysis and Signaling Pathway Impact Analysis, respectively. The gene and protein expression data of age- and stage-matched prostate cancer specimens from The Cancer Genome Atlas were analyzed. Structural and cytoskeletal proteins were differentially expressed and statistically overrepresented between RC-77 N/E and RC-77 T/E cells. Beta-catenin, alpha-actinin-1, and filamin-A were upregulated in the tumorigenic RC-77 T/E cells, while integrin beta-1, integrin alpha-6, caveolin-1, laminin subunit gamma-2, and CD44 antigen were downregulated. The increased protein level of beta-catenin and the reduction of caveolin-1 protein level in the tumorigenic RC-77 T/E cells mirrored the upregulation of beta-catenin mRNA and downregulation of caveolin-1 mRNA in African-American prostate cancer specimens compared to non-malignant controls. After subtracting race-specific non-malignant RNA expression, beta-catenin and caveolin-1 mRNA expression levels were higher in African-American prostate cancer specimens than in Caucasian-American specimens. The "ECM-Receptor Interaction" and "Cell Adhesion Molecules", and the "Tight Junction" and "Adherens Junction" pathways contained proteins are associated with RC-77 N/E and RC-77 T/E cells, respectively. Our results suggest RC-77 T/E and RC-77 N/E cell lines can be distinguished by differentially expressed structural and cytoskeletal proteins, which appeared in several pathways across multiple analyses. Our results indicate that the expression of beta-catenin and caveolin-1 may be prostate cancer- and race-specific. Although the RC-77 cell model may not be representative of all African-American prostate cancer due to tumor heterogeneity, it is a unique resource for studying prostate cancer initiation and progression.
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Date Issued: 2017-07-11
Identifier: FSU_pmch_28697756, 10.1186/s12885-017-3462-7, PMC5504803, 28697756, 28697756, 10.1186/s12885-017-3462-7
Format: Citation

Title: Exploring Background Mutational Processes To Decipher Cancer Genetic Heterogeneity.
Creator: Goncearenco, Alexander, Rager, Stephanie L., Li, Minghui, Sang, Qing-Xiang, Rogozin, Igor B., Panchenko, Anna R.
Abstract/Description: Much remains unknown about the progression and heterogeneity of mutational processes in different cancers and their diagnostic and clinical potential. A growing body of evidence supports mutation rate dependence on the local DNA sequence context for various types of mutations. We propose several tools for the analysis of cancer context-dependent mutations, which are implemented in an online computational framework MutaGene. The framework explores DNA context-dependent mutational patterns and...
Show moreMuch remains unknown about the progression and heterogeneity of mutational processes in different cancers and their diagnostic and clinical potential. A growing body of evidence supports mutation rate dependence on the local DNA sequence context for various types of mutations. We propose several tools for the analysis of cancer context-dependent mutations, which are implemented in an online computational framework MutaGene. The framework explores DNA context-dependent mutational patterns and underlying somatic cancer mutagenesis, analyzes mutational profiles of cancer samples, identifies the combinations of underlying mutagenic processes including those related to infidelity of DNA replication and repair machinery, and various other endogenous and exogenous mutagenic factors. As a result, the combination of mutagenic processes can be identified in any query sample with subsequent comparison to mutational profiles derived from malignant and benign samples. In addition, mutagen or cancer-specific mutational background models are applied to calculate expected DNA and protein site mutability to decouple relative contributions of mutagenesis and selection in carcinogenesis, thus elucidating the site-specific driving events in cancer. MutaGene is freely available at https://www.ncbi.nlm.nih.gov/projects/mutagene/.
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Date Issued: 2017-07-03
Identifier: FSU_libsubv1_wos_000404427000078, 10.1093/nar/gkx367
Format: Citation

Title: Exploring background mutational processes to decipher cancer genetic heterogeneity.
Creator: Goncearenco, Alexander, Rager, Stephanie L, Li, Minghui, Sang, Qing-Xiang, Rogozin, Igor B, Panchenko, Anna R
Abstract/Description: Much remains unknown about the progression and heterogeneity of mutational processes in different cancers and their diagnostic and clinical potential. A growing body of evidence supports mutation rate dependence on the local DNA sequence context for various types of mutations. We propose several tools for the analysis of cancer context-dependent mutations, which are implemented in an online computational framework MutaGene. The framework explores DNA context-dependent mutational patterns and...
Show moreMuch remains unknown about the progression and heterogeneity of mutational processes in different cancers and their diagnostic and clinical potential. A growing body of evidence supports mutation rate dependence on the local DNA sequence context for various types of mutations. We propose several tools for the analysis of cancer context-dependent mutations, which are implemented in an online computational framework MutaGene. The framework explores DNA context-dependent mutational patterns and underlying somatic cancer mutagenesis, analyzes mutational profiles of cancer samples, identifies the combinations of underlying mutagenic processes including those related to infidelity of DNA replication and repair machinery, and various other endogenous and exogenous mutagenic factors. As a result, the combination of mutagenic processes can be identified in any query sample with subsequent comparison to mutational profiles derived from malignant and benign samples. In addition, mutagen or cancer-specific mutational background models are applied to calculate expected DNA and protein site mutability to decouple relative contributions of mutagenesis and selection in carcinogenesis, thus elucidating the site-specific driving events in cancer. MutaGene is freely available at https://www.ncbi.nlm.nih.gov/projects/mutagene/.
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Date Issued: 2017-07-03
Identifier: FSU_pmch_28472504, 10.1093/nar/gkx367, PMC5793731, 28472504, 28472504, 3796332
Format: Citation

Title: Ion Environments in Mn2+ -Doped Polyelectrolyte Complexes: Dilute Magnetic Saloplastics.
Creator: Abhyankar, Nandita, Ghoussoub, Yara E., Wang, Qifeng, Dalal, Naresh S., Schlenoff, Joseph B.
Abstract/Description: Amorphous hydrated complexes of the polyelectrolytes poly(styrene sulfonate) (PSS) and poly(diallyldimethylammonium) (PDADMA) were doped with the spin-5/2 ion Mn2+. Xband electron paramagnetic resonance (EPR) measurements of the Mn2+ spins within this stoichiometric polyelectrolyte complex (PEC) revealed an octahedral coordination environment, similar to that observed in aqueous solutions of Mn2+. This octahedral symmetry of the [Mn(H2O)6] 2+ complexes, observed in the fully hydrated PECs, is...
Show moreAmorphous hydrated complexes of the polyelectrolytes poly(styrene sulfonate) (PSS) and poly(diallyldimethylammonium) (PDADMA) were doped with the spin-5/2 ion Mn2+. Xband electron paramagnetic resonance (EPR) measurements of the Mn2+ spins within this stoichiometric polyelectrolyte complex (PEC) revealed an octahedral coordination environment, similar to that observed in aqueous solutions of Mn2+. This octahedral symmetry of the [Mn(H2O)6] 2+ complexes, observed in the fully hydrated PECs, is somewhat distorted due to the wide range of ion pairs possible with sulfonate groups on PSS. As the Mn2+ concentration was increased, the linewidths were broadened, indicating the dominance of dipolar broadening over exchange narrowing in determining the linewidths, i.e. any exchange narrowing was masked by the large dipolar broadening. The calculated linewidths were used to estimate the strength of the dipolar interactions, and hence the distances between the Mn2+ spins, based on a simple model of regularly spaced spins. The distances calculated by this method were roughly comparable to the geometric average distances calculated on the basis of the Mn2+ concentrations and densities of the doped PEC samples. From a comparison of their EPR spectra, ion environments in the doped, fully hydrated PECs were found to be similar to those in hydrated classical ion exchange resins. EPR spectra before and after drying of the PECs indicate the replacement of octahedrally coordinated water by oxide anions from the polyanion chain, and the corresponding loss of the symmetric environment of Mn2+ ions.
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Date Issued: 2017-07-01
Identifier: FSU_libsubv1_scholarship_submission_1540239466_01912b85, 10.1021/acs.jpcb.6b02697
Format: Citation

Title: Antidiabetic Disruptors of the Glucokinase-Glucokinase Regulatory Protein Complex Reorganize a Coulombic Interface.
Creator: Martinez, Juliana A, Xiao, Qing, Zakarian, Armen, Miller, Brian G
Abstract/Description: The glucokinase regulatory protein (GKRP) plays an essential role in glucose homeostasis by acting as a competitive inhibitor of glucokinase (GCK) and triggering its localization to the hepatocyte nucleus upon glucose deprivation. Metabolites such as fructose 6-phosphate and sorbitol 6-phosphate promote assembly of the GCK-GKRP complex, whereas fructose 1-phosphate and functionalized piperazines with potent in vivo antidiabetic activity disrupt the complex. Here, we establish the molecular...
Show moreThe glucokinase regulatory protein (GKRP) plays an essential role in glucose homeostasis by acting as a competitive inhibitor of glucokinase (GCK) and triggering its localization to the hepatocyte nucleus upon glucose deprivation. Metabolites such as fructose 6-phosphate and sorbitol 6-phosphate promote assembly of the GCK-GKRP complex, whereas fructose 1-phosphate and functionalized piperazines with potent in vivo antidiabetic activity disrupt the complex. Here, we establish the molecular basis by which these natural and synthetic ligands modulate the GCK-GKRP interaction. We demonstrate that a small-molecule disruptor of the protein-protein interaction utilizes a two-step conformational selection mechanism to associate with a rare GKRP conformation constituting 3% of the total population. Conformational heterogeneity of GKRP is localized to the N-terminus and deleting this region eliminates the ability of sorbitol 6-phosphate to promote the GCK-GKRP interaction. Stabilizing ligands favor an extended N-terminus, which sterically positions two arginine residues for optimal Coulombic interaction with a pair of carboxylate side chains from GCK. Conversely, disruptors promote a more compact N-terminus in which an interfacial arginine residue is stabilized in an unproductive orientation through a cation-π interaction with tyrosine 75. Eliminating the ability to sample this binding impaired conformation enhances the intrinsic inhibitory activity of GKRP. Elucidating the molecular basis of ligand-mediated control over the GCK-GKRP interaction is expected to impact the development and future refinement of therapeutic agents for diabetes and cardiovascular disease, which result from improper GKRP regulation of GCK.
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Date Issued: 2017-06-20
Identifier: FSU_pmch_28516783, 10.1021/acs.biochem.7b00377, PMC5831357, 28516783, 28516783
Format: Citation

Title: The Impact of DNA Topology and Guide Length on Target Selection by a Cytosine-Specific Cas9.
Creator: Tsui, Tsz Kin Martin, Hand, Travis H, Duboy, Emily C, Li, Hong
Abstract/Description: Cas9 is an RNA-guided DNA cleavage enzyme being actively developed for genome editing and gene regulation. To be cleaved by Cas9, a double stranded DNA, or the protospacer, must be complementary to the guide region, typically 20-nucleotides in length, of the Cas9-bound guide RNA, and adjacent to a short Cas9-specific element called Protospacer Adjacent Motif (PAM). Understanding the correct juxtaposition of the protospacer- and PAM-interaction with Cas9 will enable development of versatile...
Show moreCas9 is an RNA-guided DNA cleavage enzyme being actively developed for genome editing and gene regulation. To be cleaved by Cas9, a double stranded DNA, or the protospacer, must be complementary to the guide region, typically 20-nucleotides in length, of the Cas9-bound guide RNA, and adjacent to a short Cas9-specific element called Protospacer Adjacent Motif (PAM). Understanding the correct juxtaposition of the protospacer- and PAM-interaction with Cas9 will enable development of versatile and safe Cas9-based technology. We report identification and biochemical characterization of Cas9 from Acidothermus cellulolyticus (AceCas9). AceCas9 depends on a 5'-NNNCC-3' PAM and is more efficient in cleaving negative supercoils than relaxed DNA. Kinetic as well as in vivo activity assays reveal that AceCas9 achieves optimal activity when combined with a guide RNA containing a 24-nucleotide complementarity region. The cytosine-specific, DNA topology-sensitive, and extended guide-dependent properties of AceCas9 may be explored for specific genome editing applications.
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Date Issued: 2017-06-16
Identifier: FSU_pmch_28277645, 10.1021/acssynbio.7b00050, PMC5706465, 28277645, 28277645
Format: Citation

Title: Upregulation of minichromosome maintenance complex component 3 during epithelial-to-mesenchymal transition in human prostate cancer.
Creator: Stewart, Paul A, Khamis, Zahraa I, Zhau, Haiyen E, Duan, Peng, Li, Quanlin, Chung, Leland W K, Sang, Qing-Xiang Amy
Abstract/Description: Metastasis is often associated with epithelial-to-mesenchymal transition (EMT). To understand the molecular mechanisms of this process, we conducted proteomic analysis of androgen-repressed cancer of the prostate (ARCaP), an experimental model of metastatic human prostate cancer. The protein signatures of epithelial (ARCaPE) and mesenchymal (ARCaPM) cells were consistent with their phenotypes. Importantly, the expression of mini-chromosome maintenance 3 (MCM3) protein, a crucial subunit of...
Show moreMetastasis is often associated with epithelial-to-mesenchymal transition (EMT). To understand the molecular mechanisms of this process, we conducted proteomic analysis of androgen-repressed cancer of the prostate (ARCaP), an experimental model of metastatic human prostate cancer. The protein signatures of epithelial (ARCaPE) and mesenchymal (ARCaPM) cells were consistent with their phenotypes. Importantly, the expression of mini-chromosome maintenance 3 (MCM3) protein, a crucial subunit of DNA helicase, was significantly higher in ARCaPM cells than that of ARCaPE cells. This increased MCM3 protein expression level was verified using Western blot analysis of the ARCaP cell lineages. Furthermore, immunohistochemical analysis of MCM3 protein levels in human prostate tissue specimens showed elevated expression in bone metastasis and advanced human prostate cancer tissue samples. Subcutaneous injection experiments using ARCaPE and ARCaPM cells in a mouse model also revealed increased MCM3 protein levels in mesenchymal-derived tumors. This study identifies MCM3 as an upregulated molecule in mesenchymal phenotype of human prostate cancer cells and advanced human prostate cancer specimens, suggesting MCM3 may be a new potential drug target for prostate cancer treatment.
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Date Issued: 2017-06-13
Identifier: FSU_pmch_28424404, 10.18632/oncotarget.16835, PMC5503607, 28424404, 28424404, 16835
Format: Citation

Title: Upregulation Of Minichromosome Maintenance Complex Component 3 During Epithelial-to-mesenchymal Transition In Human Prostate Cancer.
Creator: Stewart, Paul A., Khamis, Zahraa I., Zhau, Haiyen E., Duan, Peng, Li, Quanlin, Chung, Leland W. K., Sang, Qing-Xiang Amy
Abstract/Description: Metastasis is often associated with epithelial-to-mesenchymal transition (EMT). To understand the molecular mechanisms of this process, we conducted proteomic analysis of androgen-repressed cancer of the prostate (ARCaP), an experimental model of metastatic human prostate cancer. The protein signatures of epithelial (ARCaP(E)) and mesenchymal (ARCaPM) cells were consistent with their phenotypes. Importantly, the expression of mini-chromosome maintenance 3 (MCM3) protein, a crucial subunit of...
Show moreMetastasis is often associated with epithelial-to-mesenchymal transition (EMT). To understand the molecular mechanisms of this process, we conducted proteomic analysis of androgen-repressed cancer of the prostate (ARCaP), an experimental model of metastatic human prostate cancer. The protein signatures of epithelial (ARCaP(E)) and mesenchymal (ARCaPM) cells were consistent with their phenotypes. Importantly, the expression of mini-chromosome maintenance 3 (MCM3) protein, a crucial subunit of DNA helicase, was significantly higher in ARCaP(M) cells than that of ARCaP(E) cells. This increased MCM3 protein expression level was verified using Western blot analysis of the ARCaP cell lineages. Furthermore, immunohistochemical analysis of MCM3 protein levels in human prostate tissue specimens showed elevated expression in bone metastasis and advanced human prostate cancer tissue samples. Subcutaneous injection experiments using ARCaP(E) and ARCaP(M) cells in a mouse model also revealed increased MCM3 protein levels in mesenchymal-derived tumors. This study identifies MCM3 as an upregulated molecule in mesenchymal phenotype of human prostate cancer cells and advanced human prostate cancer specimens, suggesting MCM3 may be a new potential drug target for prostate cancer treatment.
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Date Issued: 2017-06-13
Identifier: FSU_libsubv1_wos_000403311900096, 10.18632/oncotarget.16835
Format: Citation

Title: The Solution Assembly of Biological Molecules Using Ion Mobility Methods: From Amino Acids to Amyloid β-Protein..
Creator: Bleiholder, Christian, Bowers, Michael T
Abstract/Description: Ion mobility spectrometry-mass spectrometry (IMS-MS) methods are increasingly used to study noncovalent assemblies of peptides and proteins. This review focuses on the noncovalent self-assembly of amino acids and peptides, systems at the heart of the amyloid process that play a central role in a number of devastating diseases. Three different systems are discussed in detail: the 42-residue peptide amyloid-β42 implicated in the etiology of Alzheimer's disease, several amyloid-forming peptides...
Show moreIon mobility spectrometry-mass spectrometry (IMS-MS) methods are increasingly used to study noncovalent assemblies of peptides and proteins. This review focuses on the noncovalent self-assembly of amino acids and peptides, systems at the heart of the amyloid process that play a central role in a number of devastating diseases. Three different systems are discussed in detail: the 42-residue peptide amyloid-β42 implicated in the etiology of Alzheimer's disease, several amyloid-forming peptides with 6-11 residues, and the assembly of individual amino acids. We also discuss from a more fundamental perspective the processes that determine how quickly proteins and their assemblies denature when the analyte ion has been stripped of its solvent in an IMS-MS measurement and how to soften the measurement so that biologically meaningful data can be recorded.
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Date Issued: 2017-06-12
Identifier: FSU_pmch_28375705, 10.1146/annurev-anchem-071114-040304, PMC6287953, 28375705, 28375705
Format: Citation

Title: Cas6 processes tight and relaxed repeat RNA via multiple mechanisms: A hypothesis..
Creator: Sefcikova, Jana, Roth, Mitchell, Yu, Ge, Li, Hong
Abstract/Description: RNA molecules are flexible yet foldable. Proteins must cope with this structural duality when forming biologically active complexes with RNA. Recent studies of the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs)-mediated RNA immunity illustrate some remarkable mechanisms with which proteins interact with RNA. Currently known structures of CRISPR-Cas6 endoribonucleases bound with RNA suggest a conserved protein recognition mechanism mediated by RNA stem-loops. However, a...
Show moreRNA molecules are flexible yet foldable. Proteins must cope with this structural duality when forming biologically active complexes with RNA. Recent studies of the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs)-mediated RNA immunity illustrate some remarkable mechanisms with which proteins interact with RNA. Currently known structures of CRISPR-Cas6 endoribonucleases bound with RNA suggest a conserved protein recognition mechanism mediated by RNA stem-loops. However, a survey of CRISPR RNA reveals that many repeats either lack a productive stem-loop (Relaxed) or possess stable but inhibitory structures (Tight), which raises the question of how the enzyme processes structurally diverse RNA. In reviewing recent literature, we propose a bivalent trapping and an unwinding mechanism for CRISPR-Cas6 to interact with the Relaxed and the Tight repeat RNA, respectively. Both mechanisms aim to create an identical RNA conformation at the cleavage site for accurate processing.
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Date Issued: 2017-06-01
Identifier: FSU_pmch_28493337, 10.1002/bies.201700019, PMC5699886, 28493337, 28493337
Format: Citation

Title: Overcoming The Crystallization And Designability Issues In The Ultrastable Zirconium Phosphonate Framework System.
Creator: Zheng, Tao, Yang, Zaixing, Gui, Daxiang, Liu, Zhiyong, Wang, Xiangxiang, Dai, Xing, Liu, Shengtang, Zhang, Linjuan, Gao, Yang, Chen, Lanhua, Sheng, Daopeng, Wang, Yanlong, Diwu,...
Show moreZheng, Tao, Yang, Zaixing, Gui, Daxiang, Liu, Zhiyong, Wang, Xiangxiang, Dai, Xing, Liu, Shengtang, Zhang, Linjuan, Gao, Yang, Chen, Lanhua, Sheng, Daopeng, Wang, Yanlong, Diwu, Juan, Wang, Jianqiang, Zhou, Ruhong, Chai, Zhifang, Albrecht-Schmitt, Thomas E., Wang, Shuao
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Abstract/Description: Metal-organic frameworks (MOFs) based on zirconium phosphonates exhibit superior chemical stability suitable for applications under harsh conditions. These compounds mostly exist as poorly crystallized precipitates, and precise structural information has therefore remained elusive. Furthermore, a zero-dimensional zirconium phosphonate cluster acting as secondary building unit has been lacking, leading to poor designability in this system. Herein, we overcome these challenges and obtain single...
Show moreMetal-organic frameworks (MOFs) based on zirconium phosphonates exhibit superior chemical stability suitable for applications under harsh conditions. These compounds mostly exist as poorly crystallized precipitates, and precise structural information has therefore remained elusive. Furthermore, a zero-dimensional zirconium phosphonate cluster acting as secondary building unit has been lacking, leading to poor designability in this system. Herein, we overcome these challenges and obtain single crystals of three zirconium phosphonates that are suitable for structural analysis. These compounds are built by previously unknown isolated zirconium phosphonate clusters and exhibit combined high porosity and ultrastability even in fuming acids. SZ-2 possesses the largest void volume recorded in zirconium phosphonates and SZ-3 represents the most porous crystalline zirconium phosphonate and the only porous MOF material reported to survive in aqua regia. SZ-2 and SZ-3 can effectively remove uranyl ions from aqueous solutions over a wide pH range, and we have elucidated the removal mechanism.
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Date Issued: 2017-05-30
Identifier: FSU_libsubv1_wos_000402303600001, 10.1038/ncomms15369
Format: Citation

Title: Overcoming the crystallization and designability issues in the ultrastable zirconium phosphonate framework system.
Creator: Zheng, Tao, Yang, Zaixing, Gui, Daxiang, Liu, Zhiyong, Wang, Xiangxiang, Dai, Xing, Liu, Shengtang, Zhang, Linjuan, Gao, Yang, Chen, Lanhua, Sheng, Daopeng, Wang, Yanlong, Diwu,...
Show moreZheng, Tao, Yang, Zaixing, Gui, Daxiang, Liu, Zhiyong, Wang, Xiangxiang, Dai, Xing, Liu, Shengtang, Zhang, Linjuan, Gao, Yang, Chen, Lanhua, Sheng, Daopeng, Wang, Yanlong, Diwu, Juan, Wang, Jianqiang, Zhou, Ruhong, Chai, Zhifang, Albrecht-Schmitt, Thomas E, Wang, Shuao
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Abstract/Description: Metal-organic frameworks (MOFs) based on zirconium phosphonates exhibit superior chemical stability suitable for applications under harsh conditions. These compounds mostly exist as poorly crystallized precipitates, and precise structural information has therefore remained elusive. Furthermore, a zero-dimensional zirconium phosphonate cluster acting as secondary building unit has been lacking, leading to poor designability in this system. Herein, we overcome these challenges and obtain single...
Show moreMetal-organic frameworks (MOFs) based on zirconium phosphonates exhibit superior chemical stability suitable for applications under harsh conditions. These compounds mostly exist as poorly crystallized precipitates, and precise structural information has therefore remained elusive. Furthermore, a zero-dimensional zirconium phosphonate cluster acting as secondary building unit has been lacking, leading to poor designability in this system. Herein, we overcome these challenges and obtain single crystals of three zirconium phosphonates that are suitable for structural analysis. These compounds are built by previously unknown isolated zirconium phosphonate clusters and exhibit combined high porosity and ultrastability even in fuming acids. SZ-2 possesses the largest void volume recorded in zirconium phosphonates and SZ-3 represents the most porous crystalline zirconium phosphonate and the only porous MOF material reported to survive in aqua regia. SZ-2 and SZ-3 can effectively remove uranyl ions from aqueous solutions over a wide pH range, and we have elucidated the removal mechanism.
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Date Issued: 2017-05-30
Identifier: FSU_pmch_28555656, 10.1038/ncomms15369, PMC5459948, 28555656, 28555656, ncomms15369
Format: Citation

Title: Static and Dynamic Solution Behavior of a Polyzwitterion Using a Hofmeister Salt Series.
Creator: Delgado, Jose D., Schlenoff, Joseph
Abstract/Description: Polymers made from zwitterionic repeat units (bearing no net charge) have intriguing solution properties, especially in contrast to polyelectrolytes, such as an apparent indifference to salt concentration. These polyzwitterions, PZs, have come under renewed scrutiny because of their use in high performance antifouling coatings. Here, an amidosulfobetaine polymer was used to shed light on the complex and poorly-understood response of PZ solution conformation to ionic strength. A Hofmeister...
Show morePolymers made from zwitterionic repeat units (bearing no net charge) have intriguing solution properties, especially in contrast to polyelectrolytes, such as an apparent indifference to salt concentration. These polyzwitterions, PZs, have come under renewed scrutiny because of their use in high performance antifouling coatings. Here, an amidosulfobetaine polymer was used to shed light on the complex and poorly-understood response of PZ solution conformation to ionic strength. A Hofmeister anion series NaX, where X = SO4 2, Cl-, Br-, NO3-, ClO4- and SCN provided a systematic way to tune PZ/ion interactions. A consistent picture of PZ conformation emerged, where the role and location of counterions (how they pair with the polymer chain) depends on their position in the Hofmeister series. At least four regimes of PZ conformation/interaction as a function of ionic strength were observed, the last showing no change in coil size (hydrodynamic radius) as a function of ionic strength for all salts in the concentration range 0.6 M – 4 M. Hydrophobic (less hydrated) anions ClO4- and SCN yielded a clear minimum in coil size at lower [NaX] whereas PZ in solutions of hydrophilic ions SO4- and Cl showed only a hint of the much-discussed “antipolyelectrolyte” expansion of PZ with increasing [NaX]. Static light scattering results, when analyzed using Stockmeyer’s theory of scattering from multicomponent systems, revealed that NaX is associated with PZ with a corresponding increase in apparent molecular weight. Light scattering measurements at low [NaX] show solution ions are excluded from PZ coils dressed with hydrophobic NaX. DLS in salt-free solutions at elevated temperatures revealed substantial chain stiffening of PZ, thought to be caused by nearest-neighbor interactions between zwitterion groups. DLS yielded a fast mode in these salt free solutions, ascribed to soliton-like transport of waves of associated zwitterionic groups along the PZ backbone.
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Date Issued: 2017-05-25
Identifier: FSU_libsubv1_scholarship_submission_1540240683_30337f56, 10.1021/acs.macromol.7b00525
Format: Citation

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