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Long C, Cao H, Zhao B, Tan Y, He Y, Huang C, Guan Z. Merging the Non‐Natural Catalytic Activity of Lipase and Electrosynthesis: Asymmetric Oxidative Cross‐Coupling of Secondary Amines with Ketones. Angew Chem Int Ed Engl 2022; 61:e202203666. [DOI: 10.1002/anie.202203666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Chao‐Jiu Long
- Key Laboratory of Applied Chemistry of Chongqing Municipality School of Chemistry and Chemical Engineering Southwest University Chongqing 400715 China
| | - Huan Cao
- Key Laboratory of Applied Chemistry of Chongqing Municipality School of Chemistry and Chemical Engineering Southwest University Chongqing 400715 China
| | - Ben‐Kun Zhao
- Key Laboratory of Applied Chemistry of Chongqing Municipality School of Chemistry and Chemical Engineering Southwest University Chongqing 400715 China
| | - Yu‐Fang Tan
- Key Laboratory of Applied Chemistry of Chongqing Municipality School of Chemistry and Chemical Engineering Southwest University Chongqing 400715 China
| | - Yan‐Hong He
- Key Laboratory of Applied Chemistry of Chongqing Municipality School of Chemistry and Chemical Engineering Southwest University Chongqing 400715 China
| | - Chu‐Sheng Huang
- College of Chemistry and Materials, Guangxi Key Laboratory of Natural Polymer Chemistry and Physics, Nanning Normal University Nanning 530001 China
| | - Zhi Guan
- Key Laboratory of Applied Chemistry of Chongqing Municipality School of Chemistry and Chemical Engineering Southwest University Chongqing 400715 China
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2
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Long CJ, Cao H, Zhao BK, Tan YF, He YH, Huang CS, Guan Z. Merging the Non‐Natural Catalytic Activity of Lipase and Electrosynthesis: Asymmetric Oxidative Cross‐Coupling of Secondary Amines with Ketones. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Chao-Jiu Long
- Southwest University School of Chemistry and Chemical Engineering CHINA
| | - Huan Cao
- Southwest University School of Chemistry and Chemical Engineering CHINA
| | - Ben-Kun Zhao
- Southwest University School of Chemistry and Chemical Engineering CHINA
| | - Yu-Fang Tan
- Southwest University School of Chemistry and Chemical Engineering CHINA
| | - Yan-Hong He
- Southwest University School of Chemistry and Chemical Engineering CHINA
| | - Chu-Sheng Huang
- Guangxi Teachers Education University: Nanning Normal University School of Chemistry and Chemical Engineering CHINA
| | - Zhi Guan
- Southwest University School of Chemistry and Chemical Engineering No. 1, Tiansheng Rd. 400715 Chongqing CHINA
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3
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Jian Y, Han Y, Fu Z, Xia M, Jiang G, Lu D, Wu J, Liu Z. The role of conformational dynamics on the activity of polymer-conjugated CalB in organic solvents. Phys Chem Chem Phys 2022; 24:22028-22037. [DOI: 10.1039/d2cp02208g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A perennial interest in enzyme catalysis has been expanding its applicability from aqueous phase where enzymes are naturally evolved to organic solvents in which the majority of industrial chemical synthesis...
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Lopez AJ, Barros EP, Martínez L. On the Interpretation of subtilisin Carlsberg Time-Resolved Fluorescence Anisotropy Decays: Modeling with Classical Simulations. J Chem Inf Model 2020; 60:747-755. [PMID: 31524394 DOI: 10.1021/acs.jcim.9b00539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In this work, we discuss the challenging time-resolved fluorescence anisotropy of subtilisin Carlsberg (SC), which contains a single Trp residue and is a model fluorescence system. Experimental decay rates and quenching data suggest that the fluorophore should be exposed to water, but the Trp is partially buried in a hydrophobic pocket in the crystallographic structure. In order to study this inconsistency, molecular dynamics simulations were performed to predict the anisotropy decay rates and emission wavelengths of the Trp. We confirmed the inconsistency of the crystallographic structure with the experimentally observed fluorescence data and performed free energy calculations to show that the buried Trp conformation is 2 orders of magnitude (∼3 kcal/mol) more stable than the solvent-exposed one. However, molecular dynamics simulations in which the Trp side chain was restricted to solvent-exposed conformations displayed a maximum Trp emission wavelength shifted toward lower energies and decay rates compatible with the experimentally probed rates. Therefore, if the solvent-exposed conformations are the most important emitters, the experimental anisotropy can be compatibilized with the crystallographic structure. The most likely explanation is that the fluorescence of the most probable conformation in solution, observed in the crystal, is quenched, and this is consistent with the low quantum yield of Trp113 of SC. Additionally, some experiments might have probed denatured or lysed SC structures. SC anisotropy provides an interesting target for the study of fluorescence anisotropy using simulations, which can be used to test and exemplify how modeling can aid the interpretation of experimental data in a system where structure and solution experiments appear to be inconsistent.
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Affiliation(s)
- Alvaro J Lopez
- Institute of Chemistry and Center for Computing in Engineering & Science , University of Campinas , 13083-861 Campinas - SP , Brazil
| | - Emília P Barros
- Institute of Chemistry and Center for Computing in Engineering & Science , University of Campinas , 13083-861 Campinas - SP , Brazil
| | - Leandro Martínez
- Institute of Chemistry and Center for Computing in Engineering & Science , University of Campinas , 13083-861 Campinas - SP , Brazil
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5
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Duboué-Dijon E, Pluhařová E, Domin D, Sen K, Fogarty AC, Chéron N, Laage D. Coupled Valence-Bond State Molecular Dynamics Description of an Enzyme-Catalyzed Reaction in a Non-Aqueous Organic Solvent. J Phys Chem B 2017; 121:7027-7041. [PMID: 28675789 DOI: 10.1021/acs.jpcb.7b03102] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enzymes are widely used in nonaqueous solvents to catalyze non-natural reactions. While experimental measurements showed that the solvent nature has a strong effect on the reaction kinetics, the molecular details of the catalytic mechanism in nonaqueous solvents have remained largely elusive. Here we study the transesterification reaction catalyzed by the paradigm subtilisin Carlsberg serine protease in an organic apolar solvent. The rate-limiting acylation step involves a proton transfer between active-site residues and the nucleophilic attack of the substrate to form a tetrahedral intermediate. We design the first coupled valence-bond state model that simultaneously describes both reactions in the enzymatic active site. We develop a new systematic procedure to parametrize this model on high-level ab initio QM/MM free energy calculations that account for the molecular details of the active site and for both substrate and protein conformational fluctuations. Our calculations show that the reaction energy barrier changes dramatically with the solvent and protein conformational fluctuations. We find that the mechanism of the tetrahedral intermediate formation during the acylation step is similar to that determined under aqueous conditions, and that the proton transfer and nucleophilic attack reactions occur concertedly. We identify the reaction coordinate to be mostly due to the rearrangement of some residual water molecules close to the active site.
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Affiliation(s)
- Elise Duboué-Dijon
- École Normale Supérieure - PSL Research University , Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France
| | - Eva Pluhařová
- École Normale Supérieure - PSL Research University , Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France
| | - Dominik Domin
- École Normale Supérieure - PSL Research University , Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France
| | - Kakali Sen
- École Normale Supérieure - PSL Research University , Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France
| | - Aoife C Fogarty
- École Normale Supérieure - PSL Research University , Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France
| | - Nicolas Chéron
- École Normale Supérieure - PSL Research University , Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France
| | - Damien Laage
- École Normale Supérieure - PSL Research University , Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France
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6
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Abstract
A mathematical framework is developed for analysis of solvent dependent reaction rates and selectivity in the case of complex catalytic reactions by incorporating solvent permittivity into the rate expressions.
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Kasireddy C, Bann JG, Mitchell-Koch KR. Demystifying fluorine chemical shifts: electronic structure calculations address origins of seemingly anomalous (19)F-NMR spectra of fluorohistidine isomers and analogues. Phys Chem Chem Phys 2015; 17:30606-12. [PMID: 26524669 PMCID: PMC4643390 DOI: 10.1039/c5cp05502d] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Fluorine NMR spectroscopy is a powerful tool for studying biomolecular structure, dynamics, and ligand binding, yet the origins of (19)F chemical shifts are not well understood. Herein, we use electronic structure calculations to describe the changes in (19)F chemical shifts of 2F- and 4F-histidine/(5-methyl)-imidazole upon acid titration. While the protonation of the 2F species results in a deshielded chemical shift, protonation of the 4F isomer results in an opposite, shielded chemical shift. The deshielding of 2F-histidine/(5-methyl)-imidazole upon protonation can be rationalized by concomitant decreases in charge density on fluorine and a reduced dipole moment. These correlations do not hold for 4F-histidine/(5-methyl)-imidazole, however. Molecular orbital calculations reveal that for the 4F species, there are no lone pair electrons on the fluorine until protonation. Analysis of a series of 4F-imidazole analogues, all with delocalized fluorine electron density, indicates that the deshielding of (19)F chemical shifts through substituent effects correlates with increased C-F bond polarity. In summary, the delocalization of fluorine electrons in the neutral 4F species, with gain of a lone pair upon protonation may help explain the difficulty in developing a predictive framework for fluorine chemical shifts. Ideas debated by chemists over 40 years ago, regarding fluorine's complex electronic effects, are shown to have relevance for understanding and predicting fluorine NMR spectra.
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Affiliation(s)
- Chandana Kasireddy
- Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260-0051, USA.
| | - James G Bann
- Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260-0051, USA.
| | - Katie R Mitchell-Koch
- Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260-0051, USA.
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8
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Narayanan A, Jones LH. Sulfonyl fluorides as privileged warheads in chemical biology. Chem Sci 2015; 6:2650-2659. [PMID: 28706662 PMCID: PMC5489032 DOI: 10.1039/c5sc00408j] [Citation(s) in RCA: 343] [Impact Index Per Article: 38.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/16/2015] [Indexed: 01/10/2023] Open
Abstract
The use of sulfonyl fluoride probes in chemical biology is reviewed.
Sulfonyl fluoride electrophiles have found significant utility as reactive probes in chemical biology and molecular pharmacology. As warheads they possess the right balance of biocompatibility (including aqueous stability) and protein reactivity. Their functionality is privileged in this regard as they are known to modify not only reactive serines (resulting in their common use as protease inhibitors), but also context-specific threonine, lysine, tyrosine, cysteine and histidine residues. This review describes the application of sulfonyl fluoride probes across various areas of research and explores new approaches that could further enhance the chemical biology toolkit. We believe that sulfonyl fluoride probes will find greater utility in areas such as covalent enzyme inhibition, target identification and validation, and the mapping of enzyme binding sites, substrates and protein–protein interactions.
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Affiliation(s)
- Arjun Narayanan
- Chemical Biology Group , BioTherapeutics Chemistry , WorldWide Medicinal Chemistry , Pfizer , 610 Main Street , Cambridge , MA 02139 , USA .
| | - Lyn H Jones
- Chemical Biology Group , BioTherapeutics Chemistry , WorldWide Medicinal Chemistry , Pfizer , 610 Main Street , Cambridge , MA 02139 , USA .
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9
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Liang YR, Chen XY, Wu Q, Lin XF. Diastereoselective synthesis of spirooxindole derivatives via biocatalytic domino reaction. Tetrahedron 2015. [DOI: 10.1016/j.tet.2014.12.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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10
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Liu ZQ, Xiang ZW, Shen Z, Wu Q, Lin XF. Enzymatic enantioselective aldol reactions of isatin derivatives with cyclic ketones under solvent-free conditions. Biochimie 2014; 101:156-60. [DOI: 10.1016/j.biochi.2014.01.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 01/07/2014] [Indexed: 10/25/2022]
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13
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Protease-catalysed direct asymmetric Mannich reaction in organic solvent. Sci Rep 2012; 2:761. [PMID: 23094136 PMCID: PMC3478581 DOI: 10.1038/srep00761] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 10/02/2012] [Indexed: 11/10/2022] Open
Abstract
We reported the first enzyme-catalysed, direct, three-component asymmetric Mannich reaction using protease type XIV from Streptomyces griseus (SGP) in acetonitrile. Yields of up to 92% with enantioselectivities of up to 88% e.e. and diastereoselectivities of up to 92:8 (syn:anti) were achieved under the optimised conditions. This enzyme's catalytic promiscuity expands the application of this biocatalyst and provides a potential alternative method for asymmetric Mannich reactions.
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Liszka MJ, Clark ME, Schneider E, Clark DS. Nature Versus Nurture: Developing Enzymes That Function Under Extreme Conditions. Annu Rev Chem Biomol Eng 2012; 3:77-102. [DOI: 10.1146/annurev-chembioeng-061010-114239] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | | | - Elizabeth Schneider
- Department of Chemical and Biomolecular Engineering,
- UC Berkeley and UCSF Graduate Program in Bioengineering, University of California, Berkeley, California 94720; , , ,
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15
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Gerig JT. Investigation of Methanol–Peptide Nuclear Overhauser Effects through Molecular Dynamics Simulations. J Phys Chem B 2012; 116:1965-73. [DOI: 10.1021/jp211098v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- J. T. Gerig
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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16
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Strompen S, Weiss M, Ingram T, Smirnova I, Gröger H, Hilterhaus L, Liese A. Kinetic investigation of a solvent-free, chemoenzymatic reaction sequence towards enantioselective synthesis of a β-amino acid ester. Biotechnol Bioeng 2012; 109:1479-89. [PMID: 22275046 DOI: 10.1002/bit.24422] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 12/10/2011] [Accepted: 12/19/2011] [Indexed: 11/10/2022]
Abstract
A solvent-free, chemoenzymatic reaction sequence for the enantioselective synthesis of β-amino acid esters has been kinetically and thermodynamically characterized. The coupled sequence comprises a thermal aza-Michael addition of cheap starting materials and a lipase catalyzed aminolysis for the kinetic resolution of the racemic ester. Excellent ee values of >99% were obtained for the β-amino acid ester at 60% conversion. Kinetic constants for the aza-Michael addition were obtained by straightforward numerical integration of second-order rate equations and nonlinear fitting of the progress curves. A different strategy had to be devised for the biocatalytic reaction. Initially, a simplified Michaelis-Menten model including product inhibition was developed for the reaction running in THF as an organic solvent. Activity based parameters were used instead of concentrations in order to facilitate the transfer of the kinetic model to the solvent-free system. Observed solvent effects not accounted for by the use of thermodynamic activities were incorporated into the kinetic model. Enzyme deactivation was observed to depend on the ratio of the applied substrates and also included in the kinetic model. The developed simple model is in very good agreement with the experimental data and allows the simulation and optimization of the solvent-free process.
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Affiliation(s)
- Simon Strompen
- Hamburg University of Technology, Institute of Technical Biocatalysis, Denickestr. 15, 21073 Hamburg, Germany
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17
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Xu KL, Guan Z, He YH. Acidic proteinase from Aspergillus usamii catalyzed Michael addition of ketones to nitroolefins. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.molcatb.2011.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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18
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Silvestre-Ryan J, Lin Y, Chu JW. "Fluctuograms" reveal the intermittent intra-protein communication in subtilisin Carlsberg and correlate mechanical coupling with co-evolution. PLoS Comput Biol 2011; 7:e1002023. [PMID: 21455286 PMCID: PMC3063751 DOI: 10.1371/journal.pcbi.1002023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 02/13/2011] [Indexed: 11/21/2022] Open
Abstract
The mechanism of intra-protein communication and allosteric coupling is key to understanding the structure-property relationship of protein function. For subtilisin Carlsberg, the Ca2+-binding loop is distal to substrate-binding and active sites, yet the serine protease function depends on Ca2+ binding. The atomic molecular dynamics (MD) simulations of apo and Ca2+-bound subtilisin show similar structures and there is no direct evidence that subtilisin has alternative conformations. To model the intra-protein communication due to Ca2+ binding, we transform the sequential segments of an atomic MD trajectory into separate elastic network models to represent anharmonicity and nonlinearity effectively as the temporal and spatial variation of the mechanical coupling network. In analogy to the spectrogram of sound waves, this transformation is termed the “fluctuogram” of protein dynamics. We illustrate that the Ca2+-bound and apo states of subtilisin have different fluctuograms and that intra-protein communication proceeds intermittently both in space and in time. We found that residues with large mechanical coupling variation due to Ca2+ binding correlate with the reported mutation sites selected by directed evolution for improving the stability of subtilisin and its activity in a non-aqueous environment. Furthermore, we utilize the fluctuograms calculated from MD to capture the highly correlated residues in a multiple sequence alignment. We show that in addition to the magnitude, the variance of coupling strength is also an indicative property for the sequence correlation observed in a statistical coupling analysis. The results of this work illustrate that the mechanical coupling networks calculated from atomic details can be used to correlate with functionally important mutation sites and co-evolution. A hallmark of protein molecules is their machine-like behaviors while carrying out biological functions. At the molecular level, molecular signals such as binding a metal ion at an action site can cause long-range effects and alter protein function. Such phenomena are often referred to as intra-protein communication or allosteric coupling. Elucidating the underlying mechanisms could lead to novel discovery of molecular modulators to regulate protein function in a more specific and effective manner. A long-standing puzzle is the roles of the anharmonicity and nonlinearity in protein dynamics. To incorporate these characters in modeling intra-protein communication, we devise a “fluctuogram” analysis to record the choreography of allosteric coupling in an atomic molecular dynamics simulation. We show that fluctuogram analysis can bridge the results of physics-based simulation and sequence alignment in bioinformatics by capturing the residues that exhibit high correlation in a multiple sequence alignment. We also show that the fluctuograms calculated from atomic details have the potential to be applied as a tool to select mutation sites for modulating protein function.
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Affiliation(s)
- Jordi Silvestre-Ryan
- Department of Bioengineering, University of California, Berkeley, Berkeley, California, United States of America
| | - Yuchun Lin
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California, United States of America
| | - Jhih-Wei Chu
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California, United States of America
- * E-mail:
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19
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Holder PG, Finley DT, Stephanopoulos N, Walton R, Clark DS, Francis MB. Dramatic thermal stability of virus-polymer conjugates in hydrophobic solvents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:17383-8. [PMID: 20964388 DOI: 10.1021/la1039305] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We have developed a method for integrating the self-assembling tobacco mosaic virus capsid into hydrophobic solvents and hydrophobic polymers. The capsid was modified at tyrosine residues to display an array of linear poly(ethylene glycol) chains, allowing it to be transferred into chloroform. In a subsequent step, the capsids could be transferred to a variety of hydrophobic solvents, including benzyl alcohol, o-dichlorobenzene, and diglyme. The thermal stability of the material against denaturation increased from 70 °C in water to at least 160 °C in hydrophobic solvents. With a view toward material fabrication, the polymer-coated TMV rods were also incorporated into solid polystyrene and thermally cast at 110 °C. Overall, this process significantly expands the range of processing conditions for TMV-based materials, with the goal of incorporating these templated nanoscale systems into conductive polymer matrices.
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Affiliation(s)
- Patrick G Holder
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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20
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Paravidino M, Sorgedrager MJ, Orru RVA, Hanefeld U. Activity and enantioselectivity of the hydroxynitrile lyase MeHNL in dry organic solvents. Chemistry 2010; 16:7596-604. [PMID: 20486110 PMCID: PMC2970910 DOI: 10.1002/chem.201000487] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Indexed: 11/23/2022]
Abstract
Water concentration affects both the enantioselectivity and activity of enzymes in dry organic media. Its influence has been investigated using the hydrocyanation of benzaldehyde catalyzed by hydroxynitrile lyase cross-linked enzyme aggregate (MeHNL-CLEA) as a model reaction. The enzyme displayed higher enantioselectivity at higher water concentration, thus suggesting a positive effect of enzyme flexibility on selectivity. The activity increased on reducing the solvent water content, but drastic dehydration of the enzyme resulted in a reversible loss of activity.
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Affiliation(s)
- Monica Paravidino
- Gebouw voor Scheikunde, Afdeling Biotechnologie, Technische Universiteit Delft, Julianalaan 136, 2628 BL Delft, The Netherlands
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Bansal V, Delgado Y, Fasoli E, Ferrer A, Griebenow K, Secundo F, Barletta GL. Effect of prolonged exposure to organic solvents on the active site environment of subtilisin Carlsberg. JOURNAL OF MOLECULAR CATALYSIS. B, ENZYMATIC 2010; 64:38-44. [PMID: 20414456 PMCID: PMC2856654 DOI: 10.1016/j.molcatb.2010.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The potential of enzyme catalysis as a tool for organic synthesis is nowadays indisputable, as is the fact that organic solvents affect an enzyme's activity, selectivity and stability. Moreover, it was recently realized that an enzyme's initial activity is substantially decreased after prolonged exposure to organic media, an effect that further hampers their potential as catalysts for organic synthesis. Regrettably, the mechanistic reasons for these effects are still debatable. In the present study we have made an attempt to explain the reasons behind the partial loss of enzyme activity on prolonged exposure to organic solvents. Fluorescence spectroscopic studies of the serine protease subtilisin Carlsberg chemically modified with polyethylene glycol (PEG-SC) and inhibited with a Dancyl fluorophore, and dissolved in two organic solvents (acetonitrile and 1,4-dioxane) indicate that when the enzyme is initially introduced into these solvents, the active site environment is similar to that in water; however prolonged exposure to the organic medium causes this environment to resemble that of the solvent in which the enzyme is dissolved. Furthermore, kinetic studies show a reduction on both V(max) and K(M) as a result of prolonged exposure to the solvents. One interpretation of these results is that during this prolonged exposure to organic solvents the active-site fluorescent label inhibitor adopts a different binding conformation. Extrapolating this to an enzymatic reaction we argue that substrates bind in a less catalytically favorable conformation after the enzyme has been exposed to organic media for several hours.
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Affiliation(s)
- Vibha Bansal
- University of Puerto Rico at Humacao, Department of Chemistry, Humacao, Puerto Rico, 00791
| | - Yamixa Delgado
- University of Puerto Rico at Humacao, Department of Chemistry, Humacao, Puerto Rico, 00791
| | - Ezio Fasoli
- University of Puerto Rico at Humacao, Department of Chemistry, Humacao, Puerto Rico, 00791
| | - Amaris Ferrer
- University of Puerto Rico at Humacao, Department of Chemistry, Humacao, Puerto Rico, 00791
| | - Kai Griebenow
- University of Puerto Rico at Rio Piedras, Department of Chemistry, Milano, Italy
| | - Francesco Secundo
- Istituto di Chimica del Riconoscimento Molecolare, v. M. Bianco, Milano, Italy
| | - Gabriel L Barletta
- University of Puerto Rico at Humacao, Department of Chemistry, Humacao, Puerto Rico, 00791
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22
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Surfactant-Stabilized Small Hydrogel Particles in Oil: Hosts for Remarkable Activation of Enzymes in Organic Solvents. Chemistry 2010; 16:4911-22. [DOI: 10.1002/chem.200903205] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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