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Koner D, Salehi SM, Mondal P, Meuwly M. Non-conventional force fields for applications in spectroscopy and chemical
reaction dynamics. J Chem Phys 2020; 153:010901. [DOI: 10.1063/5.0009628] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Debasish Koner
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel,
Switzerland
| | - Seyedeh Maryam Salehi
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel,
Switzerland
| | - Padmabati Mondal
- Indian Institute of Science Education and Research (IISER) Tirupati, Karakambadi Road, Mangalam, Tirupati 517507, Andhra
Pradesh, India
| | - Markus Meuwly
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel,
Switzerland and Department of Chemistry, Brown University, Providence, Rhode Island, USA
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2
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Multistate Reactive Molecular Dynamics Simulations of Proton Diffusion in Water Clusters and in the Bulk. J Phys Chem B 2019; 123:9846-9861. [PMID: 31647873 DOI: 10.1021/acs.jpcb.9b03258] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The molecular mechanics with proton transfer (MMPT) force field is combined with multistate adiabatic reactive molecular dynamics (MS-ARMD) to describe proton transport in the condensed phase. Parametrization for small protonated water clusters based on electronic structure calculations at the MP2/6-311+G(2d,2p) level of theory and refinement by comparing with infrared spectra for a protonated water tetramer yields a force field which faithfully describes the minimum energy structures of small protonated water clusters. In protonated water clusters up to (H2O)100H+, the proton hopping rate is around 100 hops/ns. This rate converges for 21 ≤ n ≤ 31, and no further speedup in bulk water is found. This indicates that bulklike behavior requires the solvation of a Zundel motif by ∼25 water molecules, which corresponds to the second solvation sphere. For smaller cluster sizes, the number of available states (i.e., the number of proton acceptors) is too small and slows down proton-transfer rates. The cluster simulations confirm that the excess proton is typically located on the surface. The free-energy surface as a function of the weights of the two lowest states and a configurational parameter suggests that the "special pair" plays a central role in rapid proton transport. The barriers between this minimum-energy structure and the Zundel and Eigen minima are sufficiently low (∼1 kcal/mol, consistent with recent experiments and commensurate with a hopping rate of ∼100/ns or 1 every 10 ps), leading to a highly dynamic environment. These findings are also consistent with recent experiments which find that Zundel-type hydration geometries are prevalent in bulk water.
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Meuwly M. Reactive molecular dynamics: From small molecules to proteins. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2018. [DOI: 10.1002/wcms.1386] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Markus Meuwly
- Department of Chemistry University of Basel Basel Switzerland
- Department of Chemistry Brown University Providence Rhode Island
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4
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Matute RA, Yoon H, Warshel A. Exploring the mechanism of DNA polymerases by analyzing the effect of mutations of active site acidic groups in Polymerase β. Proteins 2016; 84:1644-1657. [PMID: 27488241 DOI: 10.1002/prot.25106] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/22/2016] [Indexed: 12/18/2022]
Abstract
Elucidating the catalytic mechanism of DNA polymerase is crucial for a progress in the understanding of the control of replication fidelity. This work tries to advance the mechanistic understanding by analyzing the observed effect of mutations of the acidic groups in the active site of Polymerase β as well as the pH effect on the rate constant. The analysis involves both empirical valence bond (EVB) free energy calculations and considerations of the observed pH dependence of the reaction. The combined analysis indicates that the proton transfer (PT) from the nucleophilic O3' has two possible pathways, one to D256 and the second to the bulk. We concluded based on calculations and the experimental pH profile that the most likely path for the wild-type (WT) and the D256E and D256A mutants is a PT to the bulk, although the WT may also use a PT to Asp 256. Our analysis highlights the need for very extensive sampling in the calculations of the activation barrier and also clearly shows that ab initio QM/MM calculations that do not involve extensive sampling are unlikely to give a clear quantitative picture of the reaction mechanism. Proteins 2016; 84:1644-1657. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ricardo A Matute
- Department of Chemistry, University of Southern California, 418 SGM Building, 3620 McClintock Avenue, Los Angeles, California, 90089-1062
| | - Hanwool Yoon
- Department of Chemistry, University of Southern California, 418 SGM Building, 3620 McClintock Avenue, Los Angeles, California, 90089-1062
| | - Arieh Warshel
- Department of Chemistry, University of Southern California, 418 SGM Building, 3620 McClintock Avenue, Los Angeles, California, 90089-1062.
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5
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Li Y, Hartke B. Approximate photochemical dynamics of azobenzene with reactive force fields. J Chem Phys 2013; 139:224303. [DOI: 10.1063/1.4837237] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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6
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Cave RJ, Newton MD. Multistate treatments of the electronic coupling in donor-bridge-acceptor systems: insights and caveats from a simple model. J Phys Chem A 2013; 118:7221-34. [PMID: 24266545 DOI: 10.1021/jp408913k] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We use a simple one-dimensional delta function electronic structure model (dfm) to investigate the results of a pair of multistate diabatization techniques (i.e., based on n states, with n ≥ 2) for linear DBA and DBBA (donor-bridge-acceptor) electron-transfer systems. In particular, we focus on the physical meaning of the couplings obtained from multistate methods and their relationship to two-state (n = 2) coupling elements. On the basis of the simple dfm approach, which allows exact as well as finite basis set treatment and has no many-electron effects, we conclude that for orthogonal diabatic states, it is difficult to assign clear physical significance to multistate matrix elements for coupling beyond nearest-neighbor contacts. The implications of these results for more complex multistate many-electron treatments are discussed. It is emphasized that physically meaningful coupling elements must involve states that are orthogonal, either explicitly or implicitly.
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Affiliation(s)
- Robert J Cave
- Department of Chemistry, Harvey Mudd College , Claremont, California 91711, United States
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7
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Quantum mechanical modeling: a tool for the understanding of enzyme reactions. Biomolecules 2013; 3:662-702. [PMID: 24970187 PMCID: PMC4030948 DOI: 10.3390/biom3030662] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/17/2013] [Accepted: 09/19/2013] [Indexed: 01/16/2023] Open
Abstract
Most enzyme reactions involve formation and cleavage of covalent bonds, while electrostatic effects, as well as dynamics of the active site and surrounding protein regions, may also be crucial. Accordingly, special computational methods are needed to provide an adequate description, which combine quantum mechanics for the reactive region with molecular mechanics and molecular dynamics describing the environment and dynamic effects, respectively. In this review we intend to give an overview to non-specialists on various enzyme models as well as established computational methods and describe applications to some specific cases. For the treatment of various enzyme mechanisms, special approaches are often needed to obtain results, which adequately refer to experimental data. As a result of the spectacular progress in the last two decades, most enzyme reactions can be quite precisely treated by various computational methods.
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8
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Larsson HR, van Duin ACT, Hartke B. Global optimization of parameters in the reactive force field ReaxFF for SiOH. J Comput Chem 2013; 34:2178-89. [DOI: 10.1002/jcc.23382] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 06/17/2013] [Accepted: 06/24/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Henrik R. Larsson
- Institut für Physikalische Chemie, Christian-Albrechts-University; Olshausenstr. 40 24098 Kiel Germany
| | - Adri C. T. van Duin
- Department of Mechanical and Nuclear Engineering; The Pennsylvania State University, University Park; Pennsylvania 16802 USA
| | - Bernd Hartke
- Institut für Physikalische Chemie, Christian-Albrechts-University; Olshausenstr. 40 24098 Kiel Germany
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9
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Ram Prasad B, Kamerlin SCL, Florián J, Warshel A. Prechemistry barriers and checkpoints do not contribute to fidelity and catalysis as long as they are not rate limiting. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1288-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Lin Y, Wynveen A, Halley JW, Curtiss LA, Redfern PC. Self consistent tight binding model for dissociable water. J Chem Phys 2012; 136:174507. [PMID: 22583249 DOI: 10.1063/1.4705667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We report results of development of a self consistent tight binding model for water. The model explicitly describes the electrons of the liquid self consistently, allows dissociation of the water and permits fast direct dynamics molecular dynamics calculations of the fluid properties. It is parameterized by fitting to first principles calculations on water monomers, dimers, and trimers. We report calculated radial distribution functions of the bulk liquid, a phase diagram and structure of solvated protons within the model as well as ac conductivity of a system of 96 water molecules of which one is dissociated. Structural properties and the phase diagram are in good agreement with experiment and first principles calculations. The estimated DC conductivity of a computational sample containing a dissociated water molecule was an order of magnitude larger than that reported from experiment though the calculated ratio of proton to hydroxyl contributions to the conductivity is very close to the experimental value. The conductivity results suggest a Grotthuss-like mechanism for the proton component of the conductivity.
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Affiliation(s)
- You Lin
- Brion Technologies Incorporated, 4211 Burton Drive, Santa Clara, California 95054, USA
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11
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Rosta E, Warshel A. On the Origins of the Linear Free Energy Relationships: Exploring the Nature of the Off-Diagonal Coupling Elements in S(N)2 Reactions. J Chem Theory Comput 2012; 8:3574-3585. [PMID: 23329895 PMCID: PMC3544163 DOI: 10.1021/ct2009329] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Understanding the relationship between the adiabatic free energy profiles of chemical reactions and the underlining diabatic states is central to the description of chemical reactivity. The diabatic states form the theoretical basis of Linear Free Energy Relationships (LFERs) and thus play a major role in physical organic chemistry and related fields. However, the theoretical justification for some of the implicit LFER assumptions has not been fully established by quantum mechanical studies. This study follows our earlier works(1,2) and uses the ab initio frozen density functional theory (FDFT) method(3) to evaluate both the diabatic and adiabatic free energy surfaces and to determine the corresponding off-diagonal coupling matrix elements for a series of S(N)2 reactions. It is found that the off-diagonal coupling matrix elements are almost the same regardless of the nucleophile and the leaving group but change upon changing the central group. Furthermore, it is also found that the off diagonal elements are basically the same in gas phase and in solution, even when the solvent is explicitly included in the ab initio calculations. Furthermore, our study establishes that the FDFT diabatic profiles are parabolic to a good approximation thus providing a first principle support to the origin of LFER. These findings further support the basic approximation of the EVB treatment.
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Affiliation(s)
- Edina Rosta
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520
- Department of Chemistry, King’s College London, London, SE1 1UL, UK
| | - Arieh Warshel
- Department of Chemistry, University of Southern California, 3620 S. McClintock Ave., Los Angeles, California, 90089-1062
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12
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Lande ADL, Babcock NS, Řezáč J, Lévy B, Sanders BC, Salahub DR. Quantum effects in biological electron transfer. Phys Chem Chem Phys 2012; 14:5902-18. [DOI: 10.1039/c2cp21823b] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Pavanello M, Neugebauer J. Modelling charge transfer reactions with the frozen density embedding formalism. J Chem Phys 2011; 135:234103. [DOI: 10.1063/1.3666005] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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14
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Kamerlin SCL, Vicatos S, Dryga A, Warshel A. Coarse-grained (multiscale) simulations in studies of biophysical and chemical systems. Annu Rev Phys Chem 2011; 62:41-64. [PMID: 21034218 DOI: 10.1146/annurev-physchem-032210-103335] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recent years have witnessed an explosion in computational power, leading to attempts to model ever more complex systems. Nevertheless, there remain cases for which the use of brute-force computer simulations is clearly not the solution. In such cases, great benefit can be obtained from the use of physically sound simplifications. The introduction of such coarse graining can be traced back to the early usage of a simplified model in studies of proteins. Since then, the field has progressed tremendously. In this review, we cover both key developments in the field and potential future directions. Additionally, particular emphasis is given to two general approaches, namely the renormalization and reference potential approaches, which allow one to move back and forth between the coarse-grained (CG) and full models, as these approaches provide the foundation for CG modeling of complex systems.
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Affiliation(s)
- Shina C L Kamerlin
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
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15
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Frushicheva MP, Cao J, Warshel A. Challenges and advances in validating enzyme design proposals: the case of kemp eliminase catalysis. Biochemistry 2011; 50:3849-58. [PMID: 21443179 DOI: 10.1021/bi200063a] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One of the fundamental challenges in biotechnology and biochemistry is the ability to design effective enzymes. Despite recent progress, most of the advances on this front have been made by placing the reacting fragments in the proper places, rather than by optimizing the preorganization of the environment, which is the key factor in enzyme catalysis. Thus, rational improvement of the preorganization would require approaches capable of evaluating reliably the actual catalytic effect. This work considers the catalytic effects in different Kemp eliminases as a benchmark for a computer-aided enzyme design. It is shown that the empirical valence bond provides a powerful screening tool, with significant advantages over current alternative strategies. The insights provided by the empirical valence bond calculations are discussed with an emphasis on the ability to analyze the difference between the linear free energy relationships obtained in solution and those found in the enzymes. We also point out the trade-off between the reliability and speed of the calculations and try to determine what it takes to realize reliable computer-aided screening.
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Affiliation(s)
- Maria P Frushicheva
- Department of Chemistry, 418 SGM Building, University of Southern California, 3620 McClintock Avenue, Los Angeles, California 90089-1062, USA
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16
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de la Lande A, Řezáč J, Lévy B, Sanders BC, Salahub DR. Transmission coefficients for chemical reactions with multiple states: role of quantum decoherence. J Am Chem Soc 2011; 133:3883-94. [PMID: 21344903 DOI: 10.1021/ja107950m] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transition-state theory (TST) is a widely accepted paradigm for rationalizing the kinetics of chemical reactions involving one potential energy surface (PES). Multiple PES reaction rate constants can also be estimated within semiclassical approaches provided the hopping probability between the quantum states is taken into account when determining the transmission coefficient. In the Marcus theory of electron transfer, this hopping probability was historically calculated with models such as Landau-Zener theory. Although the hopping probability is intimately related to the question of the transition from the fully quantum to the semiclassical description, this issue is not adequately handled in physicochemical models commonly in use. In particular, quantum nuclear effects such as decoherence or dephasing are not present in the rate constant expressions. Retaining the convenient semiclassical picture, we include these effects through the introduction of a phenomenological quantum decoherence function. A simple modification to the usual TST rate constant expression is proposed: in addition to the electronic coupling, a characteristic decoherence time τ(dec) now also appears as a key parameter of the rate constant. This new parameter captures the idea that molecular systems, although intrinsically obeying quantum mechanical laws, behave semiclassically after a finite but nonzero amount of time (τ(dec)). This new degree of freedom allows a fresh look at the underlying physics of chemical reactions involving more than one quantum state. The ability of the proposed formula to describe the main physical lines of the phenomenon is confirmed by comparison with results obtained from density functional theory molecular dynamics simulations for a triplet to singlet transition within a copper dioxygen adduct relevant to the question of dioxygen activation by copper monooxygenases.
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Affiliation(s)
- Aurélien de la Lande
- Laboratoire de Chimie Physique-CNRS UMR 8000, Université Paris-Sud 11, Bât. 349, Campus d'Orsay, 15 rue Jean Perrin, 91 405 Orsay Cedex, France.
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17
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The empirical valence bond model: theory and applications. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2011. [DOI: 10.1002/wcms.10] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Kamerlin SCL, Warshel A. At the dawn of the 21st century: Is dynamics the missing link for understanding enzyme catalysis? Proteins 2010; 78:1339-75. [PMID: 20099310 PMCID: PMC2841229 DOI: 10.1002/prot.22654] [Citation(s) in RCA: 345] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Enzymes play a key role in almost all biological processes, accelerating a variety of metabolic reactions as well as controlling energy transduction, the transcription, and translation of genetic information, and signaling. They possess the remarkable capacity to accelerate reactions by many orders of magnitude compared to their uncatalyzed counterparts, making feasible crucial processes that would otherwise not occur on biologically relevant timescales. Thus, there is broad interest in understanding the catalytic power of enzymes on a molecular level. Several proposals have been put forward to try to explain this phenomenon, and one that has rapidly gained momentum in recent years is the idea that enzyme dynamics somehow contributes to catalysis. This review examines the dynamical proposal in a critical way, considering basically all reasonable definitions, including (but not limited to) such proposed effects as "coupling between conformational and chemical motions," "landscape searches" and "entropy funnels." It is shown that none of these proposed effects have been experimentally demonstrated to contribute to catalysis, nor are they supported by consistent theoretical studies. On the other hand, it is clarified that careful simulation studies have excluded most (if not all) dynamical proposals. This review places significant emphasis on clarifying the role of logical definitions of different catalytic proposals, and on the need for a clear formulation in terms of the assumed potential surface and reaction coordinate. Finally, it is pointed out that electrostatic preorganization actually accounts for the observed catalytic effects of enzymes, through the corresponding changes in the activation free energies.
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Affiliation(s)
- Shina C. L. Kamerlin
- Department of Chemistry, University of Southern California, 3620 McClintock Ave., Los Angeles CA-90089, USA
| | - Arieh Warshel
- Department of Chemistry, University of Southern California, 3620 McClintock Ave., Los Angeles CA-90089, USA
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Wang Z, Hirschi JS, Singleton DA. Recrossing and dynamic matching effects on selectivity in a Diels-Alder reaction. Angew Chem Int Ed Engl 2010; 48:9156-9. [PMID: 19876990 DOI: 10.1002/anie.200903293] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Zhihong Wang
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, USA
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20
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Kamerlin SCL, Warshel A. The EVB as a quantitative tool for formulating simulations and analyzing biological and chemical reactions. Faraday Discuss 2010; 145:71-106. [PMID: 25285029 PMCID: PMC4184467 DOI: 10.1039/b907354j] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent years have seen dramatic improvements in computer power, allowing ever more challenging problems to be approached. In light of this, it is imperative to have a quantitative model for examining chemical reactivity, both in the condensed phase and in solution, as well as to accurately quantify physical organic chemistry (particularly as experimental approaches can often be inconclusive). Similarly, computational approaches allow for great progress in studying enzyme catalysis, as they allow for the separation of the relevant energy contributions to catalysis. Due to the complexity of the problems that need addressing, there is a need for an approach that can combine reliability with an ability to capture complex systems in order to resolve long-standing controversies in a unique way. Herein, we will demonstrate that the empirical valence bond (EVB) approach provides a powerful way to connect the classical concepts of physical organic chemistry to the actual energies of enzymatic reactions by means of computation. Additionally, we will discuss the proliferation of this approach, as well as attempts to capture its basic chemistry and repackage it under different names. We believe that the EVB approach is the most powerful tool that is currently available for studies of chemical processes in the condensed phase in general and enzymes in particular, particularly when trying to explore the different proposals about the origin of the catalytic power of enzymes.
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Affiliation(s)
- Shina C. L. Kamerlin
- Department of Chemistry SGM418, University of Southern California, 3620 McClintock Ave., Los Angeles, CA-90089, USA
| | - Arieh Warshel
- Department of Chemistry SGM418, University of Southern California, 3620 McClintock Ave., Los Angeles, CA-90089, USA
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22
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Wang Z, Hirschi J, Singleton D. Recrossing and Dynamic Matching Effects on Selectivity in a Diels-Alder Reaction. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200903293] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Proton transport in carbonic anhydrase: Insights from molecular simulation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1804:332-41. [PMID: 19765680 DOI: 10.1016/j.bbapap.2009.09.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 09/03/2009] [Accepted: 09/05/2009] [Indexed: 12/14/2022]
Abstract
This article reviews the insights gained from molecular simulations of human carbonic anhydrase II (HCA II) utilizing non-reactive and reactive force fields. The simulations with a reactive force field explore protein transfer and transport via Grotthuss shuttling, while the non-reactive simulations probe the larger conformational dynamics that underpin the various contributions to the rate-limiting proton transfer event. Specific attention is given to the orientational stability of the His64 group and the characteristics of the active site water cluster, in an effort to determine both of their impact on the maximal catalytic rate. The explicit proton transfer and transport events are described by the multistate empirical valence bond (MS-EVB) method, as are alternative pathways for the excess proton charge defect to enter/leave the active site. The simulation results are interpreted in light of experimental results on the wild-type enzyme and various site-specific mutations of HCA II in order to better elucidate the key factors that contribute to its exceptional efficiency.
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Ufimtsev IS, Kalinichev AG, Martinez TJ, Kirkpatrick RJ. A multistate empirical valence bond model for solvation and transport simulations of OH- in aqueous solutions. Phys Chem Chem Phys 2009; 11:9420-30. [PMID: 19830325 DOI: 10.1039/b907859b] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
We describe a new multistate empirical valence bond (MS-EVB) model of OH(-) in aqueous solutions. This model is based on the recently proposed "charged ring" parameterization for the intermolecular interaction of hydroxyl ion with water [Ufimtsev, et al., Chem. Phys. Lett., 2007, 442, 128] and is suitable for classical molecular simulations of OH(-) solvation and transport. The model reproduces the hydration structure of OH(-)(aq) in good agreement with experimental data and the results of ab initio molecular dynamics simulations. It also accurately captures the major structural, energetic, and dynamic aspects of the proton transfer processes involving OH(-) (aq). The model predicts an approximately two-fold increase of the OH(-) mobility due to proton exchange reactions.
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Affiliation(s)
- Ivan S Ufimtsev
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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