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Nakata N, Okamoto R, Sumi T, Koga K, Morita T, Imamura H. Molecular mechanism of the common and opposing cosolvent effects of fluorinated alcohol and urea on a coiled coil protein. Protein Sci 2023; 32:e4763. [PMID: 37622187 PMCID: PMC10519159 DOI: 10.1002/pro.4763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/07/2023] [Accepted: 08/21/2023] [Indexed: 08/26/2023]
Abstract
Alcohols and urea are widely used as effective protein denaturants. Among monohydric alcohols, 2,2,2-trifluoroethanol (TFE) has large cosolvent effects as a helix stabilizer in proteins. In contrast, urea efficiently denatures ordered native structures, including helices, into coils. These opposing cosolvent effects of TFE and urea are well known, even though both preferentially bind to proteins; however, the underlying molecular mechanism remains controversial. Cosolvent-dependent relative stability between native and denatured states is rigorously related to the difference in preferential binding parameters (PBPs) between these states. In this study, GCN4-p1 with two-stranded coiled coil helices was employed as a model protein, and molecular dynamics simulations for the helix dimer and isolated coil were conducted in aqueous solutions with 2 M TFE and urea. As 2 M cosolvent aqueous solutions did not exhibit clustering of cosolvent molecules, we were able to directly investigate the molecular origin of the excess PBP without considering the enhancement effect of PBPs arising from the concentration fluctuations. The calculated excess PBPs of TFE for the helices and those of urea for the coils were consistent with experimentally observed stabilization of helix by TFE and that of coil by urea. The former was caused by electrostatic interactions between TFE and side chains of the helices, while the latter was attributed to both electrostatic and dispersion interactions between urea and the main chains. Unexpectedly, reverse-micelle-like orientations of TFE molecules strengthened the electrostatic interactions between TFE and the side chains, resulting in strengthening of TFE solvation.
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Affiliation(s)
- Noa Nakata
- Department of Chemistry, Faculty of ScienceOkayama UniversityOkayamaJapan
| | - Ryuichi Okamoto
- Graduate School of Information Science, University of HyogoKobeHyogoJapan
| | - Tomonari Sumi
- Department of Chemistry, Faculty of ScienceOkayama UniversityOkayamaJapan
- Research Institute for Interdisciplinary Science, Okayama UniversityOkayamaJapan
| | - Kenichiro Koga
- Department of Chemistry, Faculty of ScienceOkayama UniversityOkayamaJapan
- Research Institute for Interdisciplinary Science, Okayama UniversityOkayamaJapan
| | - Takeshi Morita
- Department of ChemistryGraduate School of Science, Chiba UniversityChibaJapan
| | - Hiroshi Imamura
- Department of Bio‐ScienceNagahama Institute of Bio‐Science and TechnologyNagahamaShigaJapan
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2
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Ajayi S, Asakereh I, Rezasoltani H, Davidson D, Khajehpour M. Does Urea Preferentially Interact with Amide Moieties or Nonpolar Sidechains? A Question Answered Through a Judicious Selection of Model Systems. Chemphyschem 2022; 24:e202200731. [PMID: 36478636 DOI: 10.1002/cphc.202200731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/02/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Abstract
The transfer model suggests that urea unfolds proteins mainly by increasing the solubility of the amide backbone, probably through urea-induced increase in hydrogen bonding. Other studies suggest that urea addition increases the magnitude of solvent-solute van der Waals interactions, which increases the solubility of nonpolar sidechains. More recent analyses hypothesize that urea has a similar effect in increasing the solubility of backbone and sidechain groups. In this work, we compare the effects of urea addition on the solvation of amides and alkyl groups. At first, we study the effects of urea addition upon solvent hydrogen bonding acidity and basicity through the perturbation in the fluorescence spectrum of probes 1-AN and 1-DMAN. Our results demonstrate that the solvent's hydrogen bonding properties are minimally affected by urea addition. Subsequently, we show that urea addition does not perturb the intra-molecular hydrogen bonding in salicylic acid significantly. Finally, we investigate how urea preferentially interacts with amide and alkyl groups moieties in water by comparing the effects of urea addition upon the solubility of acetaminophen and 4-tertbutylphenol. We show that urea affects amide and t-butyl solubility (lowers the transfer free energy of both amide (backbone) and alkyl (sidechain) groups) in a similar fashion. In other words, preferential interaction of urea with both moieties contributes to protein denaturation.
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Affiliation(s)
- Simisola Ajayi
- Department of Chemistry, the, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Iman Asakereh
- Department of Chemistry, the, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Hanieh Rezasoltani
- Department of Chemistry, the, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - David Davidson
- Department of Chemistry, the, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Mazdak Khajehpour
- Department of Chemistry, the, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
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3
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Rojruthai P, Sakdapipanich J, Wiriyanantawong J, Ho CC, Chaiear N. Effect of Latex Purification and Accelerator Types on Rubber Allergens Prevalent in Sulphur Prevulcanized Natural Rubber Latex: Potential Application for Allergy-Free Natural Rubber Gloves. Polymers (Basel) 2022; 14:4679. [PMID: 36365670 PMCID: PMC9654386 DOI: 10.3390/polym14214679] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/22/2022] [Accepted: 10/27/2022] [Indexed: 01/25/2024] Open
Abstract
Natural rubber (NR) gloves manufactured from NR latex are widely utilized in various applications as a personal protective device due to their exceptional barrier characteristics in infection control. However, the use of NR gloves was associated with concerns on NR protein allergy. With comprehensive leaching procedures now a common practice in NR latex glove factories to eliminate latent rubber proteins and chemical allergens, occurrences and complaints of protein allergy from medical glove users have decreased drastically over the past two decades. The present work aims to eliminate further the residual rubber allergens in NR latex through effective purification of the NR latex and compounding the thus purified latex with an established formulation for allergy-free NR for glove applications. NR latex was purified by deproteinization and saponification, respectively. Several analytical techniques were used to verify rubber allergens eliminated in the purified latexes. Saponified NR (SPNR) latex was the purified NR latex of choice since it is devoid of allergenic proteins and poses the lowest risk of Type I allergy. The purified NR latex was compounded with zinc diethyldithiocarbamate (ZDEC), zinc dibutyldithiocarbamate (ZDBC), and zinc 2-mercaptobenzothiazole (ZMBT), respectively, for glove dipping. Among the investigated accelerators, only ZDBC was not detected in the artificial sweat that came into contact with the dipped articles. Thus, it is deduced that ZDBC poses the lowest risk of Type IV allergy to consumers. Additionally, the morphological and physical properties of dipped articles were assessed. It was revealed that the dipped film from the SPNR latex compounded with ZDBC provided thinner and less yellow products with a more uniform internal structure and a tensile strength comparable to those of commercial NR gloves.
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Affiliation(s)
- Porntip Rojruthai
- Division of Chemical Industrial Process and Environment, Faculty of Science, Energy and Environment, King Mongkut’s University of Technology North Bangkok, Rayong 21120, Thailand
| | - Jitladda Sakdapipanich
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Salaya Campus, Phutthamonthon, Nakhon Pathom 73170, Thailand
| | - Jinjutha Wiriyanantawong
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Salaya Campus, Phutthamonthon, Nakhon Pathom 73170, Thailand
| | - Chee-Cheong Ho
- Sungai Long Campus, University Tunku Abdul Rahman, Cheras Kajang 43000, Malaysia
| | - Naesinee Chaiear
- Department of Community, Family and Occupational Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
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4
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Hammami F, Issaoui N, Nasr S. Investigation of hydrogen bonded structure of urea-water mixtures through Infra-red spectroscopy and non-covalent interaction (NCI) theoretical approach. COMPUT THEOR CHEM 2021. [DOI: 10.1016/j.comptc.2021.113218] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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5
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Cui H, Gu Z, Chen X, Lin L, Wang Z, Dai X, Yang Z, Liu L, Zhou R, Dong M. Stimulating antibacterial activities of graphitic carbon nitride nanosheets with plasma treatment. NANOSCALE 2019; 11:18416-18425. [PMID: 31576862 DOI: 10.1039/c9nr03797g] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
As a widely studied photoactive antibacterial nanomaterial, the intrinsic antibacterial traits of graphitic carbon nitride (g-C3N4) as a two-dimensional nanomaterial have not been reported so far. Herein, nitrogen-plasma-treated g-C3N4 (N-g-C3N4) nanosheets and their influence on bactericidal characteristics are investigated. Bactericidal rates of more than 99% have been successfully achieved for 8 kinds of foodborne pathogenic bacteria by N-g-C3N4 with 8 h incubation in the dark. The achieved rates are percentage wise 10 times higher than those for pristine g-C3N4. Cell rupture caused by direct mechanical contact between g-C3N4 nanosheets and cell membranes is observed. X-ray photoelectron spectroscopy revealed a substantial loss of surface defects and nitrogen vacancies in N-g-C3N4. Molecular dynamics simulations further indicated that the largely sealed defects of N-g-C3N4 enhanced the electrostatic attraction between inherent pores and lipid heads; thus, further insertion of N-g-C3N4 was promoted, resulting in enhanced antibacterial activity. This study establishes novel fabrication and application strategies for carbon based antibacterial nanomaterials.
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Affiliation(s)
- Haiying Cui
- School of Food & Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
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6
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Jahan I, Nayeem SM. Effect of Urea, Arginine, and Ethanol Concentration on Aggregation of 179CVNITV 184 Fragment of Sheep Prion Protein. ACS OMEGA 2018; 3:11727-11741. [PMID: 30320270 PMCID: PMC6173503 DOI: 10.1021/acsomega.8b00875] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 09/06/2018] [Indexed: 06/08/2023]
Abstract
Understanding protein aggregation is of utmost importance as it is responsible for causing several neurodegenerative diseases and one of the serious impediments in large-scale biopharmaceutical production. The prion protein is responsible for pathological states in fatal transmissible spongiform conditions, such as Creutzfeldt-Jakob disease and bovine spongiform encephalopathy. The peptide fragment 178-191 of Syrian hamster prion protein is known to be amyloidogenic. Here, we identified the fragment 179CVNITV184 as an aggregation-prone fragment in sheep prion protein. This fragment is conserved sequence among sheep and Syrian hamster prion protein and also falls in the previously identified amyloidogenic sequence. The mechanistic details of the aggregation behavior are analyzed in three different concentrations of urea, arginine, and ethanol. Urea and arginine are found to be aggregation suppressors, but ethanol enhances the protein aggregation through β-sheet formation. We have also analyzed the influence of these osmolyte on water dynamics in the presence of the octamer of this aggregation-prone fragment and correlated this water dynamics with the aggregation behavior of the octamer.
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7
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Borgohain G, Paul S. Atomistic level understanding of the stabilization of protein Trp cage in denaturing and mixed osmolyte solutions. COMPUT THEOR CHEM 2018. [DOI: 10.1016/j.comptc.2018.03.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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8
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Weber JK, Kang SG, Zhou R. Rare Dissipative Transitions Punctuate the Initiation of Chemical Denaturation in Proteins. Biophys J 2018; 114:812-821. [PMID: 29490243 DOI: 10.1016/j.bpj.2017.12.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/18/2017] [Accepted: 12/27/2017] [Indexed: 10/17/2022] Open
Abstract
Protein unfolding dynamics are bound by their degree of entropy production, a quantity that relates the amount of heat dissipated by a nonequilibrium process to a system's forward and time-reversed trajectories. We here explore the statistics of heat dissipation that emerge in protein molecules subjected to a chemical denaturant. Coupling large molecular dynamics datasets and Markov state models with the theory of entropy production, we demonstrate that dissipative processes can be rigorously characterized over the course of the urea-induced unfolding of the protein chymotrypsin inhibitor 2. By enumerating full entropy production probability distributions as a function of time, we first illustrate that distinct passive and dissipative regimes are present in the denaturation dynamics. Within the dissipative dynamical region, we next find that chymotrypsin inhibitor 2 is strongly driven into unfolded states in which the protein's hydrophobic core has been penetrated by urea molecules and disintegrated. Detailed analyses reveal that urea's interruption of key hydrophobic contacts between core residues causes many of the protein's native structural features to dissolve.
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Affiliation(s)
- Jeffrey K Weber
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York
| | - Seung-Gu Kang
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York
| | - Ruhong Zhou
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York; Department of Chemistry, Columbia University, New York, New York.
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9
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Pillai SA, Lee CF, Ray D, Aswal VK, Wang MR, Chen LJ, Bahadur P. Influence of urea on single and mixed micellar systems of Tetronics®. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2017.12.101] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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10
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11
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Sugawara K, Kuramitz H, Shinohara H. Fabrication of micromagnetic beads with molecular recognition/electron-transfer peptides for the sensing of ovalbumin. Anal Chim Acta 2017; 958:30-37. [DOI: 10.1016/j.aca.2016.12.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 12/12/2016] [Accepted: 12/16/2016] [Indexed: 12/25/2022]
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12
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13
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Zheng W, Borgia A, Buholzer K, Grishaev A, Schuler B, Best RB. Probing the Action of Chemical Denaturant on an Intrinsically Disordered Protein by Simulation and Experiment. J Am Chem Soc 2016; 138:11702-13. [PMID: 27583687 DOI: 10.1021/jacs.6b05443] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chemical denaturants are the most commonly used agents for unfolding proteins and are thought to act by better solvating the unfolded state. Improved solvation is expected to lead to an expansion of unfolded chains with increasing denaturant concentration, providing a sensitive probe of the denaturant action. However, experiments have so far yielded qualitatively different results concerning the effects of chemical denaturation. Studies using Förster resonance energy transfer (FRET) and other methods found an increase in radius of gyration with denaturant concentration, but most small-angle X-ray scattering (SAXS) studies found no change. This discrepancy therefore challenges our understanding of denaturation mechanism and more generally the accuracy of these experiments as applied to unfolded or disordered proteins. Here, we use all-atom molecular simulations to investigate the effect of urea and guanidinium chloride on the structure of the intrinsically disordered protein ACTR, which can be studied by experiment over a wide range of denaturant concentration. Using unbiased molecular simulations with a carefully calibrated denaturant model, we find that the protein chain indeed swells with increasing denaturant concentration. This is due to the favorable association of urea or guanidinium chloride with the backbone of all residues and with the side-chains of almost all residues, with denaturant-water transfer free energies inferred from this association in reasonable accord with experimental estimates. Interactions of the denaturants with the backbone are dominated by hydrogen bonding, while interactions with side-chains include other contributions. By computing FRET efficiencies and SAXS intensities at each denaturant concentration, we show that the simulation trajectories are in accord with both experiments on this protein, demonstrating that there is no fundamental inconsistency between the two types of experiment. Agreement with experiment also supports the picture of chemical denaturation described in our simulations, driven by weak association of denaturant with the protein. Our simulations support some assumptions needed for each experiment to accurately reflect changes in protein size, namely, that the commonly used FRET chromophores do not qualitatively alter the results and that possible effects such as preferential solvent partitioning into the interior of the chain do not interfere with the determination of radius of gyration from the SAXS experiments.
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Affiliation(s)
- Wenwei Zheng
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
| | - Alessandro Borgia
- Department of Biochemistry, University of Zurich , Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Karin Buholzer
- Department of Biochemistry, University of Zurich , Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Alexander Grishaev
- National Institute of Standards and Technology and the Institute for Bioscience and Biotechnology Research , Rockville, Maryland 20850, United States
| | - Benjamin Schuler
- Department of Biochemistry, University of Zurich , Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Robert B Best
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
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14
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Pisárčik M, Pupák M, Devínsky F, Almásy L, Tian Q, Bukovský M. Urea-based gemini surfactants: Synthesis, aggregation behaviour and biological activity. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.03.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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15
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Gao Y, Yang J, Fan H, Ding Y, Ye X. Insight into the effect of methylated urea on the phase transition of aqueous solutions of poly(N
-isopropylacrylamide) by microcalorimetry: Hydrogen bonding and van der Waals interactions. ACTA ACUST UNITED AC 2016. [DOI: 10.1002/polb.24018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Yating Gao
- Department of Chemical Physics; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China; Hefei Anhui 230026 China
| | - Jinxian Yang
- Department of Chemical Physics; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China; Hefei Anhui 230026 China
| | - Haiyan Fan
- Department of Chemical Physics; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China; Hefei Anhui 230026 China
| | - Yanwei Ding
- Department of Chemical Physics; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China; Hefei Anhui 230026 China
| | - Xiaodong Ye
- Department of Chemical Physics; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China; Hefei Anhui 230026 China
- CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China; Hefei Anhui 230026 China
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16
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Paul S, Paul S. Exploring the Counteracting Mechanism of Trehalose on Urea Conferred Protein Denaturation: A Molecular Dynamics Simulation Study. J Phys Chem B 2015; 119:9820-34. [DOI: 10.1021/acs.jpcb.5b01576] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Subrata Paul
- Department of Chemistry, Indian Institute of Technology, Guwahati, Assam, India-781039
| | - Sandip Paul
- Department of Chemistry, Indian Institute of Technology, Guwahati, Assam, India-781039
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17
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Structural changes in halophilic and non-halophilic proteases in response to chaotropic reagents. Protein J 2015; 33:394-402. [PMID: 25008068 DOI: 10.1007/s10930-014-9571-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Halophilic enzymes have been established for their stability and catalytic abilities under harsh operational conditions. These have been documented to withstand denaturation at high temperature, pH, organic solvents, and chaotropic agents. However, this stability is modulated by salt. The present study targets an important aspect in understanding protein-urea/GdmCl interactions using proteases from halophilic Bacillus sp. EMB9 and non-halophilic subtilisin (Carlsberg) from Bacillus licheniformis as model systems. While, halophilic protease containing 1 % (w/v) NaCl (0.17 M) retained full activity towards urea (8 M), non-halophilic protease lost about 90 % activity under similar conditions. The secondary and tertiary structure were lost in non-halophilic but preserved for halophilic protein. This effect could be due to the possible charge screening and shielding of the protein surface by Ca(2+) and Na(+) ions rendering it stable against denaturation. The dialyzed halophilic protease almost behaved like the non-halophilic counterpart. Incorporation of NaCl (up to 5 %, w/v or 0.85 M) in dialyzed EMB9 protease containing urea/GdmCl, not only helped regain of proteolytic activity but also evaded denaturing action. Deciphering the basis of this salt modulated stability amidst a denaturing milieu will provide guidelines and templates for engineering stable proteins/enzymes for biotechnological applications.
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18
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Yang J, Li S, Zhao H, Song B, Zhang G, Zhang J, Zhu Y, Han J. Molecular recognition and interaction between uracil and urea in solid-state studied by terahertz time-domain spectroscopy. J Phys Chem A 2014; 118:10927-33. [PMID: 25386785 DOI: 10.1021/jp506045q] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using terahertz time-domain spectroscopy characterization, we observe that urea is able to recognize and interact with uracil efficiently even in the solid phase without involving water or solvents. A cocrystal configuration linked by a pair of hydrogen bonds between uracil and urea was formed. The terahertz absorption spectrum of the cocrystal shows a distinct new absorption at 0.8 THz (26.7 cm(-1)), which originates from the intermolecular hydrogen bonding. Both mechanical milling and heating can accelerate the reaction efficiently. Density functional theory was adopted to simulate the vibrational modes of the cocrystal, and the results agree well with the experimental observation. Multiple techniques, including powder X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy, were performed to investigate the reaction process, and they presented supportive evidence. This work enables in-depth understanding of recognition and interaction of urea with nucleobases and comprehension of the denaturation related to RNA. We also demonstrate that terahertz spectroscopy is an effective and alternative tool for online measurement and quality control in pharmaceutical and chemical industries.
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Affiliation(s)
- Jingqi Yang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, People's Republic of China
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19
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Bandyopadhyay D, Mohan S, Ghosh SK, Choudhury N. Molecular Dynamics Simulation of Aqueous Urea Solution: Is Urea a Structure Breaker? J Phys Chem B 2014; 118:11757-68. [DOI: 10.1021/jp505147u] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dibyendu Bandyopadhyay
- Heavy water Division and ‡Theoretical Chemistry
Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Sadhana Mohan
- Heavy water Division and ‡Theoretical Chemistry
Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Swapan K. Ghosh
- Heavy water Division and ‡Theoretical Chemistry
Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Niharendu Choudhury
- Heavy water Division and ‡Theoretical Chemistry
Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
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20
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Lv M, He B, Liu Z, Xiu P, Tu Y. Charge-signal multiplication mediated by urea wires inside Y-shaped carbon nanotubes. J Chem Phys 2014; 141:044707. [DOI: 10.1063/1.4890725] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- Mei Lv
- Department of Mathematics, and Institute of Systems Biology, Shanghai University, Shanghai 200444, China
| | - Bing He
- School of Computer Engineering and Science, Shanghai University, Shanghai 200444, China
| | - Zengrong Liu
- Department of Mathematics, and Institute of Systems Biology, Shanghai University, Shanghai 200444, China
| | - Peng Xiu
- Department of Engineering Mechanics, and Soft Matter Research Center, Zhejiang University, Hangzhou 310027, China
| | - Yusong Tu
- Department of Mathematics, and Institute of Systems Biology, Shanghai University, Shanghai 200444, China
- College of Physics Science and Technology, Yangzhou University, Yangzhou 225009, China
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21
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Rodríguez-Ropero F, van der Vegt NFA. Direct Osmolyte–Macromolecule Interactions Confer Entropic Stability to Folded States. J Phys Chem B 2014; 118:7327-34. [DOI: 10.1021/jp504065e] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Francisco Rodríguez-Ropero
- Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, 64287, Darmstadt, Germany
| | - Nico F. A. van der Vegt
- Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, 64287, Darmstadt, Germany
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22
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Cai Z, Li J, Yin C, Yang Z, Wu J, Zhou R. Effect of urea concentration on aggregation of amyloidogenic hexapeptides (NFGAIL). J Phys Chem B 2013; 118:48-57. [PMID: 24328094 DOI: 10.1021/jp407776e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We have performed large-scale all-atom molecular dynamics (MD) simulations to study the aggregation behavior of four NFGAIL hexapeptides in the aqueous urea solution, with a urea concentration ranging from 0 to 5 M. We find that urea in general suppresses the peptide aggregation, but suppression slows down in the intermediation concentration regime around 3 M. Two competing mechanisms of urea are determined: urea molecules accumulated near the first solvation shell (FSS) tend to unfold the hexapeptide, which favors aggregation; on the other hand, the tight hydrogen bonds formed between urea and peptide mainchains hinder the association of peptides which disfavors the formation of the β-sheet. Furthermore, the different nonlinear urea concentration dependences of the urea-peptide and peptide-peptide hydrogen bonds lead to a nonmonotonic behavior, with a weak enhancement in the peptide aggregation around 3 M.
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Affiliation(s)
- Zhuowei Cai
- Department of Physics, Zhejiang University , Hangzhou, 310027, China
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Thapa U, Ismail K. Urea effect on aggregation and adsorption of sodium dioctylsulfosuccinate in water. J Colloid Interface Sci 2013; 406:172-7. [DOI: 10.1016/j.jcis.2013.06.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 05/30/2013] [Accepted: 06/02/2013] [Indexed: 10/26/2022]
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Carr JK, Buchanan LE, Schmidt JR, Zanni MT, Skinner JL. Structure and dynamics of urea/water mixtures investigated by vibrational spectroscopy and molecular dynamics simulation. J Phys Chem B 2013; 117:13291-300. [PMID: 23841646 DOI: 10.1021/jp4037217] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Urea/water is an archetypical "biological" mixture and is especially well-known for its relevance to protein thermodynamics as urea acts as a protein denaturant at high concentration. This behavior has given rise to an extended debate concerning urea's influence on water structure. On the basis of a variety of methods and of definitions of the water structure, urea has been variously described as a structure-breaker, a structure-maker, or as remarkably neutral toward water. Because of its sensitivity to microscopic structure and dynamics, vibrational spectroscopy can help resolve these debates. We report experimental and theoretical spectroscopic results for the OD stretch of HOD/H2O/urea mixtures (linear IR, 2DIR, and pump-probe anisotropy decay) and for the CO stretch of urea-D4/D2O mixtures (linear IR only). Theoretical results are obtained using existing approaches for water and a modification of a frequency map developed for acetamide. All absorption spectra are remarkably insensitive to urea concentration, consistent with the idea that urea only very weakly perturbs the water structure. Both this work and experiments by Rezus and Bakker, however, show that water's rotational dynamics are slowed down by urea. Analysis of the simulations casts doubt on the suggestion that urea immobilizes particular doubly hydrogen bonded water molecules.
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Affiliation(s)
- J K Carr
- Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin , Madison, Wisconsin 53706, United States
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25
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Kurzbach D, Platzer G, Schwarz TC, Henen MA, Konrat R, Hinderberger D. Cooperative unfolding of compact conformations of the intrinsically disordered protein osteopontin. Biochemistry 2013; 52:5167-75. [PMID: 23848319 PMCID: PMC3737600 DOI: 10.1021/bi400502c] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Intrinsically disordered proteins (IDPs) constitute a class of biologically active proteins that lack defined tertiary and often secondary structure. The IDP Osteopontin (OPN), a cytokine involved in metastasis of several types of cancer, is shown to simultaneously sample extended, random coil-like conformations and stable, cooperatively folded conformations. By a combination of two magnetic resonance methods, electron paramagnetic resonance and nuclear magnetic resonance spectroscopy, we demonstrate that the OPN ensemble exhibits not only characteristics of an extended and flexible polypeptide, as expected for an IDP, but also simultaneously those of globular proteins, in particular sigmoidal structural denaturation profiles. Both types of states, extended and cooperatively folded, are populated simultaneously by OPN in its apo state. The heterogeneity of the structural properties of IDPs is thus shown to even involve cooperative folding and unfolding events.
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Affiliation(s)
- Dennis Kurzbach
- Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany
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26
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Larini L, Shea JE. Double Resolution Model for Studying TMAO/Water Effective Interactions. J Phys Chem B 2013; 117:13268-77. [DOI: 10.1021/jp403635g] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Luca Larini
- Department of Chemistry
and Biochemistry
and of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, United
States
| | - Joan-Emma Shea
- Department of Chemistry
and Biochemistry
and of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, United
States
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27
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Das P, Xia Z, Zhou R. Collapse of a hydrophobic polymer in a mixture of denaturants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:4877-4882. [PMID: 23517381 DOI: 10.1021/la3046252] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The solvent quality of an aqueous mixture of two good solvents, urea and guanidinium chloride (GdmCl), for a hydrophobic polymer was investigated using atomistic molecular dynamics simulations. A counterintuitive collapse of the polymer was found, suggesting that mixing the two denaturants reduces the solvent quality. This cononsolvency of the polymer in the urea + GdmCl mixture is found to be caused by the preferential adsorption of urea on the polymer. The polymer collapses as a result of indirect long-range interactions between monomers resulting from the presence of urea clouds surrounding them. Surprisingly, urea behaves as the better solvent in the mixture not because there exists a stronger affinity of the polymer for urea. Instead, attractive interactions between two unlike denaturant molecules combined with the direct dispersion interactions of the polymer with both denaturants determine the solvent quality of the mixture.
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Affiliation(s)
- Payel Das
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States.
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28
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Pazos IM, Gai F. Solute's perspective on how trimethylamine oxide, urea, and guanidine hydrochloride affect water's hydrogen bonding ability. J Phys Chem B 2012; 116:12473-8. [PMID: 22998405 PMCID: PMC3475735 DOI: 10.1021/jp307414s] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
While the thermodynamic effects of trimethylamine oxide (TMAO), urea, and guanidine hydrochloride (GdnHCl) on protein stability are well understood, the underlying mechanisms of action are less well characterized and, in some cases, even under debate. Herein, we employ the stretching vibration of two infrared (IR) reporters, i.e., nitrile (C≡N) and carbonyl (C═O), to directly probe how these cosolvents mediate the ability of water to form hydrogen bonds with the solute of interest, e.g., a peptide. Our results show that these three agents, despite having different effects on protein stability, all act to decrease the strength of the hydrogen bonds formed between water and the infrared probe. While the behavior of TMAO appears to be consistent with its protein-protecting ability, those of urea and GdnHCl are inconsistent with their role as protein denaturants. The latter is of particular interest as it provides strong evidence indicating that although urea and GdnHCl can perturb the hydrogen-bonding property of water their protein-denaturing ability does not arise from a simple indirect mechanism.
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Affiliation(s)
- Ileana M. Pazos
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
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