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Zhang X, Wang Z, Li Z, Shaik S, Wang B. [4Fe–4S]-Mediated Proton-Coupled Electron Transfer Enables the Efficient Degradation of Chloroalkenes by Reductive Dehalogenases. ACS Catal 2023. [DOI: 10.1021/acscatal.2c06306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Xuan Zhang
- State Key Laboratory Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
| | - Zikuan Wang
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr 45470, Germany
| | - Zhen Li
- State Key Laboratory Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
| | - Sason Shaik
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Binju Wang
- State Key Laboratory Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
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2
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Xin X, Li C, Gao D, Wang D. Catalytic Descriptors to Investigate Catalytic Power in the Reaction of Haloalkane Dehalogenase Enzyme with 1,2-Dichloroethane. Int J Mol Sci 2021; 22:ijms22115854. [PMID: 34072602 PMCID: PMC8197811 DOI: 10.3390/ijms22115854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/24/2021] [Accepted: 05/27/2021] [Indexed: 11/16/2022] Open
Abstract
Enzymes play a fundamental role in many biological processes. We present a theoretical approach to investigate the catalytic power of the haloalkane dehalogenase reaction with 1,2-dichloroethane. By removing the three main active-site residues one by one from haloalkane dehalogenase, we found two reactive descriptors: one descriptor is the distance difference between the breaking bond and the forming bond, and the other is the charge difference between the transition state and the reactant complex. Both descriptors scale linearly with the reactive barriers, with the three-residue case having the smallest barrier and the zero-residue case having the largest. The results demonstrate that, as the number of residues increases, the catalytic power increases. The predicted free energy barriers using the two descriptors of this reaction in water are 23.1 and 24.2 kcal/mol, both larger than the ones with any residues, indicating that the water solvent hinders the reactivity. Both predicted barrier heights agree well with the calculated one at 25.2 kcal/mol using a quantum mechanics and molecular dynamics approach, and also agree well with the experimental result at 26.0 kcal/mol. This study shows that reactive descriptors can also be used to describe and predict the catalytic performance for enzyme catalysis.
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Abstract
The application of native enzymes may not be economical owing to the stability factor. A smaller protein molecule may be less susceptible to external stresses. Haloalkane dehalogenases (HLDs) that act on toxic haloalkanes may be incorporated as bioreceptors to detect haloalkane contaminants. Therefore, this study aims to develop mini proteins of HLD as an alternative bioreceptor which was able to withstand extreme conditions. Initially, the mini proteins were designed through computer modeling. Based on the results, five designed mini proteins were deemed to be viable stable mini proteins. They were then validated through experimental study. The smallest mini protein (model 5) was chosen for subsequent analysis as it was expressed in soluble form. No dehalogenase activity was detected, thus the specific binding interaction of between 1,3-dibromopropane with mini protein was investigated using isothermal titration calorimetry. Higher binding affinity between 1,3-dibromopropane and mini protein was obtained than the native. Thermal stability study with circular dichroism had proven that the mini protein possessed two times higher Tm value at 83.73 °C than the native at 43.97 °C. In conclusion, a stable mini protein was successfully designed and may be used as bioreceptors in the haloalkane sensor that is suitable for industrial application.
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Prakasam T, Devaraj A, Saha R, Lusi M, Brandel J, Esteban-Gómez D, Platas-Iglesias C, Olson MA, Mukherjee PS, Trabolsi A. Metal–Organic Self-Assembled Trefoil Knots for C—Br Bond Activation. ACS Catal 2019. [DOI: 10.1021/acscatal.8b04650] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Thirumurugan Prakasam
- New York University Abu Dhabi (NYUAD), Experimental Research Building, Building C1, Saadiyat Island, Abu Dhabi, United Arab Emirates
| | - Anthonisamy Devaraj
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore 560012, India
| | - Rupak Saha
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore 560012, India
| | - Matteo Lusi
- Department of Chemical and Environmental Science, University of Limerick, Limerick, Republic of Ireland
| | - Jeremy Brandel
- Université de Strasbourg, IPHC, 25 rue Becquerel, 67087 Strasbourg, France
- CNRS, UMR7178, 67087 Strasbourg, France
| | - David Esteban-Gómez
- Departamento de Química, Facultade de Ciencias & Centro de Investigaciones Cientı́ficas Avanzadas (CICA), Universidade da Coruña, 15071 A Coruña, Spain
| | - Carlos Platas-Iglesias
- Departamento de Química, Facultade de Ciencias & Centro de Investigaciones Cientı́ficas Avanzadas (CICA), Universidade da Coruña, 15071 A Coruña, Spain
| | - Mark Anthony Olson
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Partha Sarathi Mukherjee
- Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore 560012, India
| | - Ali Trabolsi
- New York University Abu Dhabi (NYUAD), Experimental Research Building, Building C1, Saadiyat Island, Abu Dhabi, United Arab Emirates
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5
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Crystallographic and Computational Characterization of Methyl Tetrel Bonding in S-Adenosylmethionine-Dependent Methyltransferases. Molecules 2018; 23:molecules23112965. [PMID: 30428636 PMCID: PMC6278250 DOI: 10.3390/molecules23112965] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 10/19/2018] [Accepted: 10/20/2018] [Indexed: 11/17/2022] Open
Abstract
Tetrel bonds represent a category of non-bonding interaction wherein an electronegative atom donates a lone pair of electrons into the sigma antibonding orbital of an atom in the carbon group of the periodic table. Prior computational studies have implicated tetrel bonding in the stabilization of a preliminary state that precedes the transition state in SN2 reactions, including methyl transfer. Notably, the angles between the tetrel bond donor and acceptor atoms coincide with the prerequisite geometry for the SN2 reaction. Prompted by these findings, we surveyed crystal structures of methyltransferases in the Protein Data Bank and discovered multiple instances of carbon tetrel bonding between the methyl group of the substrate S-adenosylmethionine (AdoMet) and electronegative atoms of small molecule inhibitors, ions, and solvent molecules. The majority of these interactions involve oxygen atoms as the Lewis base, with the exception of one structure in which a chlorine atom of an inhibitor functions as the electron donor. Quantum mechanical analyses of a representative subset of the methyltransferase structures from the survey revealed that the calculated interaction energies and spectral properties are consistent with the values for bona fide carbon tetrel bonds. The discovery of methyl tetrel bonding offers new insights into the mechanism underlying the SN2 reaction catalyzed by AdoMet-dependent methyltransferases. These findings highlight the potential of exploiting these interactions in developing new methyltransferase inhibitors.
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6
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Miranda-Rojas S, Fernández I, Kästner J, Toro-Labbé A, Mendizábal F. Unraveling the Nature of the Catalytic Power of Fluoroacetate Dehalogenase. ChemCatChem 2018. [DOI: 10.1002/cctc.201701517] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sebastián Miranda-Rojas
- Departamento de Ciencias Químicas; Facultad de Ciencias Exactas; Universidad Andres Bello; Av. República 275 Santiago Chile
| | - Israel Fernández
- Departamento de Química Orgánica I and Centro de Innovación en, Química Avanzada (ORFEO-CINQA); Facultad de Ciencias Químicas; Universidad Complutense de Madrid; 28040- Madrid Spain
| | - Johannes Kästner
- Institut für Theoretische Chemie; Universität Stuttgart; Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Alejandro Toro-Labbé
- Laboratorio de Química Teórica Computacional; Facultad de Química; Pontifica Universidad Católica de Chile; Av. Vicuña Mackenna 4860, Macul Santiago Chile
| | - Fernando Mendizábal
- Departamento de Química; Facultad de Ciencias; Universidad de Chile; Las Palmeras 3425, Ñuñoa Santiago Chile
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Elementary S N 2 reaction revisited. Effects of solvent and alkyl chain length on kinetics of halogen exchange in haloalkanes elucidated by Empirical Valence Bond simulation. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2017.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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8
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Stare J. Complete sampling of an enzyme reaction pathway: a lesson from gas phase simulations. RSC Adv 2017. [DOI: 10.1039/c6ra27894a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
With proper sampling strategy, convergence of free energy profiles of biomolecular reactions in the gas phase can be achieved in microseconds of simulation.
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Affiliation(s)
- Jernej Stare
- Department of Computational Biochemistry and Drug Design
- National Institute of Chemistry
- SI-1000 Ljubljana
- Slovenia
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9
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Hopmann KH, Himo F. Quantum Chemical Modeling of the Dehalogenation Reaction of Haloalcohol Dehalogenase. J Chem Theory Comput 2015; 4:1129-37. [PMID: 26636366 DOI: 10.1021/ct8000443] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dehalogenation reaction of haloalcohol dehalogenase HheC from Agrobacterium radiobacter AD1 was investigated theoretically using hybrid density functional theory methods. HheC catalyzes the enantioselective conversion of halohydrins into their corresponding epoxides. The reaction is proposed to be mediated by a catalytic Ser132-Tyr145-Arg149 triad, and a distinct halide binding site is suggested to facilitate halide displacement by stabilizing the free ion. We investigated the HheC-mediated dehalogenation of (R)-2-chloro-1-phenylethanol using three quantum chemical models of various sizes. The calculated barriers and reaction energies give support to the suggested reaction mechanism. The dehalogenation occurs in a single concerted step, in which Tyr145 abstracts a proton from the halohydrin substrate and the substrate oxyanion displaces the chloride ion, forming the epoxide. Characterization of the involved stationary points is provided. Furthermore, by using three different models of the halide binding site, we are able to assess the adopted modeling methodology.
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Affiliation(s)
- Kathrin H Hopmann
- Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, AlbaNova University Center, SE-106 91 Stockholm, Sweden
| | - Fahmi Himo
- Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, AlbaNova University Center, SE-106 91 Stockholm, Sweden
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10
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Daniel L, Buryska T, Prokop Z, Damborsky J, Brezovsky J. Mechanism-Based Discovery of Novel Substrates of Haloalkane Dehalogenases Using in Silico Screening. J Chem Inf Model 2014; 55:54-62. [DOI: 10.1021/ci500486y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Lukas Daniel
- Loschmidt
Laboratories, Department
of Experimental Biology and Research Centre for Toxic Compounds in
the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Tomas Buryska
- Loschmidt
Laboratories, Department
of Experimental Biology and Research Centre for Toxic Compounds in
the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Zbynek Prokop
- Loschmidt
Laboratories, Department
of Experimental Biology and Research Centre for Toxic Compounds in
the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Jiri Damborsky
- Loschmidt
Laboratories, Department
of Experimental Biology and Research Centre for Toxic Compounds in
the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
| | - Jan Brezovsky
- Loschmidt
Laboratories, Department
of Experimental Biology and Research Centre for Toxic Compounds in
the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic
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11
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Kumar A, Pillay B, Olaniran AO. Cloning, expression, purification and three-dimensional structure prediction of haloalkane dehalogenase from a recently isolated Ancylobacter aquaticus strain UV5. Protein Expr Purif 2014; 99:10-7. [DOI: 10.1016/j.pep.2014.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 03/01/2014] [Accepted: 03/04/2014] [Indexed: 11/16/2022]
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12
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Wijma HJ, Marrink SJ, Janssen DB. Computationally efficient and accurate enantioselectivity modeling by clusters of molecular dynamics simulations. J Chem Inf Model 2014; 54:2079-92. [PMID: 24916632 DOI: 10.1021/ci500126x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Computational approaches could decrease the need for the laborious high-throughput experimental screening that is often required to improve enzymes by mutagenesis. Here, we report that using multiple short molecular dynamics (MD) simulations makes it possible to accurately model enantioselectivity for large numbers of enzyme-substrate combinations at low computational costs. We chose four different haloalkane dehalogenases as model systems because of the availability of a large set of experimental data on the enantioselective conversion of 45 different substrates. To model the enantioselectivity, we quantified the frequency of occurrence of catalytically productive conformations (near attack conformations) for pairs of enantiomers during MD simulations. We found that the angle of nucleophilic attack that leads to carbon-halogen bond cleavage was a critical variable that limited the occurrence of productive conformations; enantiomers for which this angle reached values close to 180° were preferentially converted. A cluster of 20-40 very short (10 ps) MD simulations allowed adequate conformational sampling and resulted in much better agreement to experimental enantioselectivities than single long MD simulations (22 ns), while the computational costs were 50-100 fold lower. With single long MD simulations, the dynamics of enzyme-substrate complexes remained confined to a conformational subspace that rarely changed significantly, whereas with multiple short MD simulations a larger diversity of conformations of enzyme-substrate complexes was observed.
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Affiliation(s)
- Hein J Wijma
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands
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Encell LP, Friedman Ohana R, Zimmerman K, Otto P, Vidugiris G, Wood MG, Los GV, McDougall MG, Zimprich C, Karassina N, Learish RD, Hurst R, Hartnett J, Wheeler S, Stecha P, English J, Zhao K, Mendez J, Benink HA, Murphy N, Daniels DL, Slater MR, Urh M, Darzins A, Klaubert DH, Bulleit RF, Wood KV. Development of a dehalogenase-based protein fusion tag capable of rapid, selective and covalent attachment to customizable ligands. CURRENT CHEMICAL GENOMICS 2012; 6:55-71. [PMID: 23248739 PMCID: PMC3520037 DOI: 10.2174/1875397301206010055] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 04/04/2012] [Accepted: 04/16/2012] [Indexed: 11/22/2022]
Abstract
Our fundamental understanding of proteins and their biological significance has been enhanced by genetic fusion tags, as they provide a convenient method for introducing unique properties to proteins so that they can be examinedin isolation. Commonly used tags satisfy many of the requirements for applications relating to the detection and isolation of proteins from complex samples. However, their utility at low concentration becomes compromised if the binding affinity for a detection or capture reagent is not adequate to produce a stable interaction. Here, we describe HaloTag® (HT7), a genetic fusion tag based on a modified haloalkane dehalogenase designed and engineered to overcome the limitation of affinity tags by forming a high affinity, covalent attachment to a binding ligand. HT7 and its ligand have additional desirable features. The tag is relatively small, monomeric, and structurally compatible with fusion partners, while the ligand is specific, chemically simple, and amenable to modular synthetic design. Taken together, the design features and molecular evolution of HT7 have resulted in a superior alternative to common tags for the overexpression, detection, and isolation of target proteins.
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15
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Nakayama T, Kamachi T, Jitsumori K, Omi R, Hirotsu K, Esaki N, Kurihara T, Yoshizawa K. Substrate specificity of fluoroacetate dehalogenase: an insight from crystallographic analysis, fluorescence spectroscopy, and theoretical computations. Chemistry 2012; 18:8392-402. [PMID: 22674735 DOI: 10.1002/chem.201103369] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 04/19/2012] [Indexed: 11/11/2022]
Abstract
The high substrate specificity of fluoroacetate dehalogenase was explored by using crystallographic analysis, fluorescence spectroscopy, and theoretical computations. A crystal structure for the Asp104Ala mutant of the enzyme from Burkholderia sp. FA1 complexed with fluoroacetate was determined at 1.2 Å resolution. The orientation and conformation of bound fluoroacetate is different from those in the crystal structure of the corresponding Asp110Asn mutant of the enzyme from Rhodopseudomonas palustris CGA009 reported recently (J. Am. Chem. Soc. 2011, 133, 7461). The fluorescence of the tryptophan residues of the wild-type and Trp150Phe mutant enzymes from Burkholderia sp. FA1 incubated with fluoroacetate and chloroacetate was measured to gain information on the environment of the tryptophan residues. The environments of the tryptophan residues were found to be different between the fluoroacetate- and chloroacetate-bound enzymes; this would come from different binding modes of these two substrates in the active site. Docking simulations and QM/MM optimizations were performed to predict favorable conformations and orientations of the substrates. The F atom of the substrate is oriented toward Arg108 in the most stable enzyme-fluoroacetate complex. This is a stable but unreactive conformation, in which the small O-C-F angle is not suitable for the S(N)2 displacement of the F(-) ion. The cleavage of the C-F bond is initiated by the conformational change of the substrate to a near attack conformation (NAC) in the active site. The second lowest energy conformation is appropriate for NAC; the C-O distance and the O-C-F angle are reasonable for the S(N) 2 reaction. The activation energy is greatly reduced in this conformation because of three hydrogen bonds between the leaving F atom and surrounding amino acid residues. Chloroacetate cannot reach the reactive conformation, due to the longer C-Cl bond; this results in an increase of the activation energy despite the weaker C-Cl bond.
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Affiliation(s)
- Tomonori Nakayama
- Institute for Materials Chemistry and Engineering and International Research Center for Molecular Systems, Kyushu University, Fukuoka 819-0395, Japan
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16
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Riazanov A, Laurila JB, Baker CJO. Deploying mutation impact text-mining software with the SADI Semantic Web Services framework. BMC Bioinformatics 2011; 12 Suppl 4:S6. [PMID: 21992079 PMCID: PMC3194198 DOI: 10.1186/1471-2105-12-s4-s6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Mutation impact extraction is an important task designed to harvest relevant annotations from scientific documents for reuse in multiple contexts. Our previous work on text mining for mutation impacts resulted in (i) the development of a GATE-based pipeline that mines texts for information about impacts of mutations on proteins, (ii) the population of this information into our OWL DL mutation impact ontology, and (iii) establishing an experimental semantic database for storing the results of text mining. RESULTS This article explores the possibility of using the SADI framework as a medium for publishing our mutation impact software and data. SADI is a set of conventions for creating web services with semantic descriptions that facilitate automatic discovery and orchestration. We describe a case study exploring and demonstrating the utility of the SADI approach in our context. We describe several SADI services we created based on our text mining API and data, and demonstrate how they can be used in a number of biologically meaningful scenarios through a SPARQL interface (SHARE) to SADI services. In all cases we pay special attention to the integration of mutation impact services with external SADI services providing information about related biological entities, such as proteins, pathways, and drugs. CONCLUSION We have identified that SADI provides an effective way of exposing our mutation impact data such that it can be leveraged by a variety of stakeholders in multiple use cases. The solutions we provide for our use cases can serve as examples to potential SADI adopters trying to solve similar integration problems.
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Affiliation(s)
- Alexandre Riazanov
- Department of Computer Science & Applied Statistics, University of New Brunswick, Saint John, New Brunswick, E2L 4L5, Canada
| | - Jonas Bergman Laurila
- Department of Computer Science & Applied Statistics, University of New Brunswick, Saint John, New Brunswick, E2L 4L5, Canada
| | - Christopher JO Baker
- Department of Computer Science & Applied Statistics, University of New Brunswick, Saint John, New Brunswick, E2L 4L5, Canada
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Westerbeek A, Szymański W, Wijma HJ, Marrink SJ, Feringa BL, Janssen DB. Kinetic Resolution of α-Bromoamides: Experimental and Theoretical Investigation of Highly Enantioselective Reactions Catalyzed by Haloalkane Dehalogenases. Adv Synth Catal 2011. [DOI: 10.1002/adsc.201000726] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Laurila JB, Naderi N, Witte R, Riazanov A, Kouznetsov A, Baker CJO. Algorithms and semantic infrastructure for mutation impact extraction and grounding. BMC Genomics 2010; 11 Suppl 4:S24. [PMID: 21143808 PMCID: PMC3005927 DOI: 10.1186/1471-2164-11-s4-s24] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Background Mutation impact extraction is a hitherto unaccomplished task in state of the art mutation extraction systems. Protein mutations and their impacts on protein properties are hidden in scientific literature, making them poorly accessible for protein engineers and inaccessible for phenotype-prediction systems that currently depend on manually curated genomic variation databases. Results We present the first rule-based approach for the extraction of mutation impacts on protein properties, categorizing their directionality as positive, negative or neutral. Furthermore protein and mutation mentions are grounded to their respective UniProtKB IDs and selected protein properties, namely protein functions to concepts found in the Gene Ontology. The extracted entities are populated to an OWL-DL Mutation Impact ontology facilitating complex querying for mutation impacts using SPARQL. We illustrate retrieval of proteins and mutant sequences for a given direction of impact on specific protein properties. Moreover we provide programmatic access to the data through semantic web services using the SADI (Semantic Automated Discovery and Integration) framework. Conclusion We address the problem of access to legacy mutation data in unstructured form through the creation of novel mutation impact extraction methods which are evaluated on a corpus of full-text articles on haloalkane dehalogenases, tagged by domain experts. Our approaches show state of the art levels of precision and recall for Mutation Grounding and respectable level of precision but lower recall for the task of Mutant-Impact relation extraction. The system is deployed using text mining and semantic web technologies with the goal of publishing to a broad spectrum of consumers.
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Affiliation(s)
- Jonas B Laurila
- Department of Computer Science & Applied Statistics, University of New Brunswick, Saint John, New Brunswick, Canada.
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19
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Theoretical QM/MM studies of enzymatic pericyclic reactions. Interdiscip Sci 2010; 2:115-31. [DOI: 10.1007/s12539-010-0095-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Revised: 12/07/2009] [Accepted: 12/09/2009] [Indexed: 11/25/2022]
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20
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Lafaquière V, Barbe S, Puech-Guenot S, Guieysse D, Cortés J, Monsan P, Siméon T, André I, Remaud-Siméon M. Control of lipase enantioselectivity by engineering the substrate binding site and access channel. Chembiochem 2010; 10:2760-71. [PMID: 19816890 DOI: 10.1002/cbic.200900439] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Lipase from Burkholderia cepacia (BCL) has proven to be a very useful biocatalyst for the resolution of 2-substituted racemic acid derivatives, which are important chiral building blocks. Our previous work showed that enantioselectivity of the wild-type BCL could be improved by chemical engineering of the substrate's molecular structure. From this earlier study, three amino acids (L17, V266 and L287) were proposed as targets for mutagenesis aimed at tailoring enzyme enantioselectivity. In the present work, a small library of 57 BCL single mutants targeted on these three residues was constructed and screened for enantioselectivity towards (R,S)-2-chloro ethyl 2-bromophenylacetate. This led to the fast isolation of three single mutants with a remarkable tenfold enhanced or reversed enantioselectivity. Analysis of substrate docking and access trajectories in the active site was then performed. From this analysis, the construction of 13 double mutants was proposed. Among them, an outstanding improved mutant of BCL was isolated that showed an E value of 178 and a 15-fold enhanced specific activity compared to the parental enzyme; thus, this study demonstrates the efficiency of the semirational engineering strategy.
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Affiliation(s)
- Vincent Lafaquière
- Université de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, 31077 Toulouse, France
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Nakamura T, Yamaguchi A, Kondo H, Watanabe H, Kurihara T, Esaki N, Hirono S, Tanaka S. Roles of K151 and D180 in L-2-haloacid dehalogenase fromPseudomonassp. YL: Analysis by molecular dynamics andab initiofragment molecular orbital calculations. J Comput Chem 2009; 30:2625-34. [DOI: 10.1002/jcc.21273] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Kamachi T, Nakayama T, Shitamichi O, Jitsumori K, Kurihara T, Esaki N, Yoshizawa K. The catalytic mechanism of fluoroacetate dehalogenase: a computational exploration of biological dehalogenation. Chemistry 2009; 15:7394-403. [PMID: 19551770 DOI: 10.1002/chem.200801813] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The biological dehalogenation of fluoroacetate carried out by fluoroacetate dehalogenase is discussed by using quantum mechanical/molecular mechanical (QM/MM) calculations for a whole-enzyme model of 10 800 atoms. Substrate fluoroacetate is anchored by a hydrogen-bonding network with water molecules and the surrounding amino acid residues of Arg105, Arg108, His149, Trp150, and Tyr212 in the active site in a similar way to haloalkane dehalogenase. Asp104 is likely to act as a nucleophile to attack the alpha-carbon of fluoroacetate, resulting in the formation of an ester intermediate, which is subsequently hydrolyzed by the nucleophilic attack of a water molecule to the carbonyl carbon atom. The cleavage of the strong C-F bond is greatly facilitated by the hydrogen-bonding interactions between the leaving fluorine atom and the three amino acid residues of His149, Trp150, and Tyr212. The hydrolysis of the ester intermediate is initiated by a proton transfer from the water molecule to His271 and by the simultaneous nucleophilic attack of the water molecule. The transition state and produced tetrahedral intermediate are stabilized by Asp128 and the oxyanion hole composed of Phe34 and Arg105.
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Affiliation(s)
- Takashi Kamachi
- Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka 819-0395, Japan
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23
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Valero R, Song L, Gao J, Truhlar DG. Perspective on Diabatic Models of Chemical Reactivity as Illustrated by the Gas-Phase S(N)2 Reaction of Acetate Ion with 1,2-Dichloroethane. J Chem Theory Comput 2009; 5:1-22. [PMID: 20047005 PMCID: PMC2658610 DOI: 10.1021/ct800318h] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Diabatic models are widely employed for studying chemical reactivity in condensed phases and enzymes, but there has been little discussion of the pros and cons of various diabatic representations for this purpose. Here we discuss and contrast six different schemes for computing diabatic potentials for a charge rearrangement reaction. They include (i) the variational diabatic configurations (VDC) constructed by variationally optimizing individual valence bond structures and (ii) the consistent diabatic configurations (CDC) obtained by variationally optimizing the ground-state adiabatic energy, both in the nonorthogonal molecular orbital valence bond (MOVB) method, along with the orthogonalized (iii) VDC-MOVB and (iv) CDC-MOVB models. In addition, we consider (v) the fourfold way (based on diabatic molecular orbitals and configuration uniformity), and (vi) empirical valence bond (EVB) theory. To make the considerations concrete, we calculate diabatic electronic states and diabatic potential energies along the reaction path that connects the reactant and the product ion-molecule complexes of the gas-phase bimolecular nucleophilic substitution (S(N)2) reaction of 1,2-dichloethane (DCE) with acetate ion, which is a model reaction corresponding to the reaction catalyzed by haloalkane dehalogenase. We utilize ab initio block-localized molecular orbital theory to construct the MOVB diabatic states and ab initio multi-configuration quasidegenerate perturbation theory to construct the fourfold-way diabatic states; the latter are calculated at reaction path geometries obtained with the M06-2X density functional. The EVB diabatic states are computed with parameters taken from the literature. The MOVB and fourfold-way adiabatic and diabatic potential energy profiles along the reaction path are in qualitative but not quantitative agreement with each other. In order to validate that these wave-function-based diabatic states are qualitatively correct, we show that the reaction energy and barrier for the adiabatic ground state, obtained with these methods, agree reasonably well with the results of high-level calculations using the composite G3SX and G3SX(MP3) methods and the BMC-CCSD multi-coefficient correlation method. However, a comparison of the EVB gas-phase adiabatic ground-state reaction path with those obtained from MOVB and with the fourfold way reveals that the EVB reaction path geometries show a systematic shift towards the products region, and that the EVB lowest-energy path has a much lower barrier. The free energies of solvation and activation energy in water reported from dynamical calculations based on EVB also imply a low activation barrier in the gas phase. In addition, calculations of the free energy of solvation using the recently proposed SM8 continuum solvation model with CM4M partial atomic charges lead to an activation barrier in reasonable agreement with experiment only when the geometries and the gas-phase barrier are those obtained from electronic structure calculations, i.e., methods i-v. These comparisons show the danger of basing the diabatic states on molecular mechanics without the explicit calculation of electronic wave functions. Furthermore, comparison of schemes i-v with one another shows that significantly different quantitative results can be obtained by using different methods for extracting diabatic states from wave function calculations, and it is important for each user to justify the choice of diabatization method in the context of its intended use.
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Affiliation(s)
- Rosendo Valero
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0431
| | - Lingchun Song
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0431
| | - Jiali Gao
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0431
| | - Donald G. Truhlar
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0431
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24
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Benighaus T, Thiel W. Efficiency and Accuracy of the Generalized Solvent Boundary Potential for Hybrid QM/MM Simulations: Implementation for Semiempirical Hamiltonians. J Chem Theory Comput 2008; 4:1600-9. [DOI: 10.1021/ct800193a] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Tobias Benighaus
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Walter Thiel
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
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25
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Wu R, Xie H, Cao Z, Mo Y. Combined Quantum Mechanics/Molecular Mechanics Study on the Reversible Isomerization of Glucose and Fructose Catalyzed by Pyrococcus furiosus Phosphoglucose Isomerase. J Am Chem Soc 2008; 130:7022-31. [DOI: 10.1021/ja710633c] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ruibo Wu
- Department of Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China, and Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008
| | - Hujun Xie
- Department of Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China, and Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008
| | - Zexing Cao
- Department of Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China, and Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008
| | - Yirong Mo
- Department of Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005, China, and Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008
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26
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Otyepka M, Banás P, Magistrato A, Carloni P, Damborský J. Second step of hydrolytic dehalogenation in haloalkane dehalogenase investigated by QM/MM methods. Proteins 2008; 70:707-17. [PMID: 17729274 DOI: 10.1002/prot.21523] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mechanistic studies on the hydrolytic dehalogenation catalyzed by haloalkane dehalogenases are of importance for environmental and industrial applications. Here, Car-Parrinello (CP) and ONIOM hybrid quantum-mechanical/molecular mechanics (QM/MM) are used investigate the second reaction step of the catalytic cycle, which comprises a general base-catalyzed hydrolysis of an ester intermediate (EI) to alcohol and free enzyme. We focus on the enzyme LinB from Sphingomonas paucimobilis UT26, for which the X-ray structure at atomic resolution is available. In agreement with previous proposals, our calculations suggest that a histidine residue (His272), polarized by glutamate (Glu132), acts as a base, accepting a proton from the catalytic water molecule and transferring it to an alcoholate ion. The reaction proceeds through a metastable tetrahedral intermediate, which shows an easily reversed reaction to the EI. In the formation of the products, the protonated aspartic acid (Asp108) can easily adopt conformation of the relaxed state found in the free enzyme. The overall free energy barrier of the reaction calculated by potential of the mean force integration using CP-QM/MM calculations is equal to 19.5 +/- 2 kcal . mol(-1). The lowering of the energy barrier of catalyzed reaction with respect to the water reaction is caused by strong stabilization of the reaction intermediate and transition state and their preorganization by electrostatic field of the enzyme.
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Affiliation(s)
- Michal Otyepka
- Department of Physical Chemistry and Center for Biomolecular and Complex Molecular Systems, Palacký University, Olomouc 771 46, Czech Republic
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27
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Rosta E, Klähn M, Warshel A. Towards accurate ab initio QM/MM calculations of free-energy profiles of enzymatic reactions. J Phys Chem B 2007; 110:2934-41. [PMID: 16471904 DOI: 10.1021/jp057109j] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reliable studies of enzymatic reactions by combined quantum mechanical/molecular mechanics (QM/MM) approaches, with an ab initio description of the quantum region, presents a major challenge to computational chemists. The main problem is the need for a large amount of computer time to evaluate the QM energy, which in turn makes it extremely challenging to perform proper configurational sampling. This work presents major progress toward the evaluation of ab initio QM/MM free-energy surfaces and activation free energies of reactions in enzymes and in solutions. This is done by exploiting our previous idea of using the empirical valence bond (EVB) method as a reference potential and then using the linear response approximation (LRA) approach to evaluate the free energies of transfer from the EVB to the QM/MM surfaces in the reactant and product state. However, the new crucial step involves the use of a constraint at the transition state that fixes the system at a given value of the reaction coordinate and allows us to use the LRA at the transition state. The advance offered by the present approach is particularly significant because it evaluates the free energy associated with both the substrate and the solvent motions. This evaluation appeared to be a relatively simple task once one uses a classical reference potential. The main problem has been using the reference potential for the evaluation of the free-energy contributions associated with the solute motions where the difference between the reference EVB potential and the QM/MM potential can be large. The present refinement finally allows us to overcome the problems with the solute fluctuations and therefore to obtain, for the first time, a free-energy barrier that reflects the solute entropy properly. Thus, we present a way to evaluate the complete QM/MM activation free energy with an equal footing treatment of the solute and the solvent. This provides a general consistent and effective strategy for evaluating the QM/MM activation free energies in proteins and in solution. Our advance allows one to explore consistently various mechanistic and catalytic proposals while using ab initio (ai) QM/MM approaches.
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Affiliation(s)
- Edina Rosta
- Department of Chemistry, University of Southern California, 3620 South McClintock Avenue, Los Angeles, California 90089-1062, USA
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28
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Pavlová M, Klvana M, Jesenská A, Prokop Z, Konecná H, Sato T, Tsuda M, Nagata Y, Damborský J. The identification of catalytic pentad in the haloalkane dehalogenase DhmA from Mycobacterium avium N85: Reaction mechanism and molecular evolution. J Struct Biol 2007; 157:384-92. [PMID: 17084094 DOI: 10.1016/j.jsb.2006.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 09/08/2006] [Accepted: 09/12/2006] [Indexed: 11/20/2022]
Abstract
Haloalkane dehalogenase DhmA from Mycobacterium avium N85 showed poor expression and low stability when produced in Escherichia coli. Here, we present expression DhmA in newly constructed pK4RP rhodococcal expression system in a soluble and stable form. Site-directed mutagenesis was used for the identification of a catalytic pentad, which makes up the reaction machinery of all currently known haloalkane dehalogenases. The putative catalytic triad Asp123, His279, Asp250 and the first halide-stabilizing residue Trp124 were deduced from sequence comparisons. The second stabilizing residue Trp164 was predicted from a homology model. Five point mutants in the catalytic pentad were constructed, tested for activity and were found inactive. A two-step reaction mechanism was proposed for DhmA. Evolution of different types of catalytic pentads and molecular adaptation towards the synthetic substrate 1,2-dichloroethane within the protein family is discussed.
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Affiliation(s)
- Martina Pavlová
- Loschmidt Laboratories, Masaryk University, Brno, Czech Republic
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29
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Haeffner F, Marquez M, Gonzalez C. Theoretical Evidence for C-F Bond Activation by a Fluoro-calix[4]pyrrole-tert-amine Macrocycle. J Phys Chem A 2006; 111:268-72. [PMID: 17214463 DOI: 10.1021/jp063387m] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Density functional theory as well as highly correlated ab initio molecular orbital theory was used to explore the possibility of activating C-F bonds in fluoroalkanes by organic macrocycles. The results indicate that the reaction between fluoro-calix [4]pyrrole-tert-amine and CH3F via a Menshutkin displacement mechanism is highly favorable and competitive from a thermochemical point of view with the very efficient C-Cl activation by a simple macrocyclic amine recently reported in the literature (Stanger, L. J.; Noll, B. C.; Gonzalez, C.; Marquez, M.; Smith, B. D. J. Am. Chem. Soc. 2005, 127, 4184).
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Affiliation(s)
- Fredrik Haeffner
- Computational Chemistry Group and Center for Theoretical and Computational Nanosciences, NIST, Gaithersburg, Maryland 20899, USA
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30
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Gao J, Ma S, Major DT, Nam K, Pu J, Truhlar DG. Mechanisms and free energies of enzymatic reactions. Chem Rev 2006; 106:3188-209. [PMID: 16895324 PMCID: PMC4477011 DOI: 10.1021/cr050293k] [Citation(s) in RCA: 317] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jiali Gao
- Department of Chemistry and Supercomputing Institute, Digital Technology Center, University of Minnesota, Minneapolis, Minnesota 55455
| | - Shuhua Ma
- Department of Chemistry and Supercomputing Institute, Digital Technology Center, University of Minnesota, Minneapolis, Minnesota 55455
| | - Dan T. Major
- Department of Chemistry and Supercomputing Institute, Digital Technology Center, University of Minnesota, Minneapolis, Minnesota 55455
| | - Kwangho Nam
- Department of Chemistry and Supercomputing Institute, Digital Technology Center, University of Minnesota, Minneapolis, Minnesota 55455
| | - Jingzhi Pu
- Department of Chemistry and Supercomputing Institute, Digital Technology Center, University of Minnesota, Minneapolis, Minnesota 55455
| | - Donald G. Truhlar
- Department of Chemistry and Supercomputing Institute, Digital Technology Center, University of Minnesota, Minneapolis, Minnesota 55455
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31
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Abstract
Mechanistic insight into the biochemistry of carbon-halogen bond cleavage is rapidly growing because of recent structural, biochemical and computational studies that have provided further insight into how haloalkane dehalogenases achieve their impressive catalytic activity. An occluded water-free active-site cavity together with strong hydrogen bond donating groups reduce the transition state energy barrier compared with that of the non-enzymatic reaction in water. Even though all known haloalkane dehalogenases belong to the alpha/beta-hydrolase fold family, there are interesting differences in mechanistic and kinetic details, as shown by properties of mutant enzymes and transient-state kinetic studies. To improve enzymatic degradation of some environmentally important recalcitrant compounds, site-directed mutagenesis and directed-evolution studies are being done.
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Affiliation(s)
- Dick B Janssen
- Biochemical Laboratory, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, The Netherlands.
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32
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Garcia-Viloca M, Gao J, Karplus M, Truhlar DG. How enzymes work: analysis by modern rate theory and computer simulations. Science 2004; 303:186-95. [PMID: 14716003 DOI: 10.1126/science.1088172] [Citation(s) in RCA: 817] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Advances in transition state theory and computer simulations are providing new insights into the sources of enzyme catalysis. Both lowering of the activation free energy and changes in the generalized transmission coefficient (recrossing of the transition state, tunneling, and nonequilibrium contributions) can play a role. A framework for understanding these effects is presented, and the contributions of the different factors, as illustrated by specific enzymes, are identified and quantified by computer simulations. The resulting understanding of enzyme catalysis is used to comment on alternative proposals of how enzymes work.
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Affiliation(s)
- Mireia Garcia-Viloca
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455, USA
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33
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Chaloupková R, Sýkorová J, Prokop Z, Jesenská A, Monincová M, Pavlová M, Tsuda M, Nagata Y, Damborský J. Modification of activity and specificity of haloalkane dehalogenase from Sphingomonas paucimobilis UT26 by engineering of its entrance tunnel. J Biol Chem 2003; 278:52622-8. [PMID: 14525993 DOI: 10.1074/jbc.m306762200] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Structural comparison of three different haloalkane dehalogenases suggested that substrate specificity of these bacterial enzymes could be significantly influenced by the size and shape of their entrance tunnels. The surface residue leucine 177 positioned at the tunnel opening of the haloalkane dehalogenase from Sphingomonas paucimobilis UT26 was selected for modification based on structural and phylogenetic analysis; the residue partially blocks the entrance tunnel, and it is the most variable pocket residue in haloalkane dehalogenase-like proteins with nine substitutions in 14 proteins. Mutant genes coding for proteins carrying all possible substitutions in position 177 were constructed by site-directed mutagenesis and heterologously expressed in Escherichia coli. In total, 15 active protein variants were obtained, suggesting a relatively high tolerance of the site for the introduction of mutations. Purified protein variants were kinetically characterized by determination of specific activities with 12 halogenated substrates and steady-state kinetic parameters with two substrates. The effect of mutation on the enzyme activities varied dramatically with the structure of the substrates, suggesting that extrapolation of one substrate to another may be misleading and that a systematic characterization of the protein variants with a number of substrates is essential. Multivariate analysis of activity data revealed that catalytic activity of mutant enzymes generally increased with the introduction of small and nonpolar amino acid in position 177. This result is consistent with the phylogenetic analysis showing that glycine and alanine are the most commonly occurring amino acids in this position among haloalkane dehalogenases. The study demonstrates the advantages of using rational engineering to develop enzymes with modified catalytic properties and substrate specificities. The strategy of using site-directed mutagenesis to modify a specific entrance tunnel residue identified by structural and phylogenetic analyses, rather than combinatorial screening, generated a high percentage of viable mutants.
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Affiliation(s)
- Radka Chaloupková
- National Centre for Biomolecular Research, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
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34
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Abstract
Recently, an alternative has been offered to the concept of transition state (TS) stabilization as an explanation for rate enhancements in enzyme-catalyzed reactions. Instead, most of the rate increase has been ascribed to preorganization of the enzyme active site to bind substrates in a geometry close to that of the TS, which then transit the activation barrier impelled by motions along the reaction coordinate. The question as to how an enzyme achieves such preorganization and concomitant TS stabilization as well as potential coupled motions along the reaction coordinate leads directly to the role of protein dynamic motion. Dihydrofolate reductase (DHFR) is a paradigm in which the role of dynamics in catalysis continues to be unraveled by a wealth of kinetic, structural, and computational studies. DHFR has flexible loop regions adjacent to the active site whose motions modulate passage through the kinetically preferred pathway. The participation of residues distant from the DHFR active site in enhancing the rate of hydride transfer, however, is unanticipated and may signify the importance of long range protein motions. The general significance of protein dynamics in understanding other biological processes is briefly discussed.
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Affiliation(s)
- P T Ravi Rajagopalan
- Department of Chemistry, Pennsylvania State University, University Park, 16802, USA
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35
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Hur S, Kahn K, Bruice TC. Comparison of formation of reactive conformers for the SN2 displacements by CH3CO2- in water and by Asp124-CO2- in a haloalkane dehalogenase. Proc Natl Acad Sci U S A 2003; 100:2215-9. [PMID: 12610210 PMCID: PMC151320 DOI: 10.1073/pnas.242721799] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The S(N)2 displacement of Cl(-) from 1,2-dichloroethane by acetate (CH(3)CO(2)(-)) in water and by the carboxylate of the active site aspartate in the haloalkane dehalogenase of Xanthobacter autothropicus have been compared by using molecular dynamics simulations. In aqueous solution, six families of contact-pair structures (I-VI) were identified, and their relative concentrations and dissociation rate constants were determined. The near attack conformers (NACs) required for the S(N)2 displacement reaction are members of the IV (CH(3)COO(-)...CH(2)(Cl)CH(2)Cl) family and are formed in the sequence II-->III-->IV-->NAC. The NAC subclass is defined by the COO(-)...CCl contact distance of < or = 3.41 A and the COO(-)...CCl angle of 157-180 degrees. The mole percentage of NACs is 0.16%, based on the 1 M standard state. This result may be compared with 13.4 mole percentage of NACs in the Michaelis complex in the enzyme. It follows that NAC formation in the enzyme is favored by 2.6 kcal/mol. Because reaction coordinates from S to TS, both in water and in the enzyme, pass via NAC (i.e., S --> NAC --> TS), the reduction in the S --> NAC barrier by 2.6 kcal/mol accounts for approximately 25% of the reduction of total barrier in the S --> TS (10.7 kcal/mol). The remaining 75% of the advantage of the enzymatic reaction revolves around the efficiency of NAC --> TS step. This process, based on previous studies, is discussed briefly.
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Affiliation(s)
- Sun Hur
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA
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36
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Abstract
This review discusses methods for the incorporation of quantum mechanical effects into enzyme kinetics simulations in which the enzyme is an explicit part of the model. We emphasize three aspects: (a) use of quantum mechanical electronic structure methods such as molecular orbital theory and density functional theory, usually in conjunction with molecular mechanics; (b) treating vibrational motions quantum mechanically, either in an instantaneous harmonic approximation, or by path integrals, or by a three-dimensional wave function coupled to classical nuclear motion; (c) incorporation of multidimensional tunneling approximations into reaction rate calculations.
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Affiliation(s)
- Jiali Gao
- Department of Chemistry and Supercomputer Institute, University of Minnesota, 207 Pleasant Street S.E., Minneapolis, Minnesota 55455-0431, USA.
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37
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Bosma T, Damborský J, Stucki G, Janssen DB. Biodegradation of 1,2,3-trichloropropane through directed evolution and heterologous expression of a haloalkane dehalogenase gene. Appl Environ Microbiol 2002; 68:3582-7. [PMID: 12089046 PMCID: PMC126774 DOI: 10.1128/aem.68.7.3582-3587.2002] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2002] [Accepted: 04/24/2002] [Indexed: 11/20/2022] Open
Abstract
Using a combined strategy of random mutagenesis of haloalkane dehalogenase and genetic engineering of a chloropropanol-utilizing bacterium, we constructed an organism that is capable of growth on 1,2,3-trichloropropane (TCP). This highly toxic and recalcitrant compound is a waste product generated from the manufacture of the industrial chemical epichlorohydrin. Attempts to select and enrich bacterial cultures that can degrade TCP from environmental samples have repeatedly been unsuccessful, prohibiting the development of a biological process for groundwater treatment. The critical step in the aerobic degradation of TCP is the initial dehalogenation to 2,3-dichloro-1-propanol. We used random mutagenesis and screening on eosin-methylene blue agar plates to improve the activity on TCP of the haloalkane dehalogenase from Rhodococcus sp. m15-3 (DhaA). A second-generation mutant containing two amino acid substitutions, Cys176Tyr and Tyr273Phe, was nearly eight times more efficient in dehalogenating TCP than wild-type dehalogenase. Molecular modeling of the mutant dehalogenase indicated that the Cys176Tyr mutation has a global effect on the active-site structure, allowing a more productive binding of TCP within the active site, which was further fine tuned by Tyr273Phe. The evolved haloalkane dehalogenase was expressed under control of a constitutive promoter in the 2,3-dichloro-1-propanol-utilizing bacterium Agrobacterium radiobacter AD1, and the resulting strain was able to utilize TCP as the sole carbon and energy source. These results demonstrated that directed evolution of a key catabolic enzyme and its subsequent recruitment by a suitable host organism can be used for the construction of bacteria for the degradation of a toxic and environmentally recalcitrant chemical.
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Affiliation(s)
- Tjibbe Bosma
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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38
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Abstract
Elucidating how enzymes enhance the rates of the reactions that they catalyze is a major goal of contemporary biochemistry, and it is an area in which computational and theoretical techniques can make a major contribution. This article outlines some of the processes that need to be investigated if enzyme catalysis is to be understood, reviews the current state-of-the-art in enzyme simulation work, and highlights challenges for the future.
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Affiliation(s)
- Martin J Field
- Laboratoire de Dynamique Moléculaire, Institut de Biologie Structurale, Grenoble, France.
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39
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Prat-Resina X, Garcia-Viloca M, González-Lafont A, Lluch JM. On the modulation of the substrate activity for the racemization catalyzed by mandelate racemase enzyme. A QM/MM study. Phys Chem Chem Phys 2002. [DOI: 10.1039/b204693h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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