51
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McGeagh JD, Ranaghan KE, Mulholland AJ. Protein dynamics and enzyme catalysis: insights from simulations. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1814:1077-92. [PMID: 21167324 DOI: 10.1016/j.bbapap.2010.12.002] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 11/25/2010] [Accepted: 12/03/2010] [Indexed: 10/18/2022]
Abstract
The role of protein dynamics in enzyme catalysis is one of the most active and controversial areas in enzymology today. Some researchers claim that protein dynamics are at the heart of enzyme catalytic efficiency, while others state that dynamics make no significant contribution to catalysis. What is the biochemist - or student - to make of the ferocious arguments in this area? Protein dynamics are complex and fascinating, as molecular dynamics simulations and experiments have shown. The essential question is: do these complex motions have functional significance? In particular, how do they affect or relate to chemical reactions within enzymes, and how are chemical and conformational changes coupled together? Biomolecular simulations can analyse enzyme reactions and dynamics in atomic detail, beyond that achievable in experiments: accurate atomistic modelling has an essential part to play in clarifying these issues. This article is part of a Special Issue entitled: Protein Dynamics: Experimental and Computational Approaches.
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Affiliation(s)
- John D McGeagh
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Cantock's Close, BS8 1TS, United Kingdom
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52
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Argyrakis W, Köppl C, Werner HJ, Frey W, Baro A, Laschat S. A combined quantum mechanical and experimental approach towards chiral diketopiperazine hydroperoxides. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1809] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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53
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Pirc G, Stare J, Mavri J. Car-Parrinello simulation of hydrogen bond dynamics in sodium hydrogen bissulfate. J Chem Phys 2010; 132:224506. [PMID: 20550407 DOI: 10.1063/1.3429251] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We studied proton dynamics of a short hydrogen bond of the crystalline sodium hydrogen bissulfate, a hydrogen-bonded ferroelectric system. Our approach was based on the established Car-Parrinello molecular dynamics (CPMD) methodology, followed by an a posteriori quantization of the OH stretching motion. The latter approach is based on snapshot structures taken from CPMD trajectory, calculation of proton potentials, and solving of the vibrational Schrodinger equation for each of the snapshot potentials. The so obtained contour of the OH stretching band has the center of gravity at about 1540 cm(-1) and a half width of about 700 cm(-1), which is in qualitative agreement with the experimental infrared spectrum. The corresponding values for the deuterated form are 1092 and 600 cm(-1), respectively. The hydrogen probability densities obtained by solving the vibrational Schrodinger equation allow for the evaluation of potential of mean force along the proton transfer coordinate. We demonstrate that for the present system the free energy profile is of the single-well type and features a broad and shallow minimum near the center of the hydrogen bond, allowing for frequent and barrierless proton (or deuteron) jumps. All the calculated time-averaged geometric parameters were in reasonable agreement with the experimental neutron diffraction data. As the present methodology for quantization of proton motion is applicable to a variety of hydrogen-bonded systems, it is promising for potential use in computational enzymology.
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Affiliation(s)
- Gordana Pirc
- National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia
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54
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Lodola A, Sirirak J, Fey N, Rivara S, Mor M, Mulholland AJ. Structural Fluctuations in Enzyme-Catalyzed Reactions: Determinants of Reactivity in Fatty Acid Amide Hydrolase from Multivariate Statistical Analysis of Quantum Mechanics/Molecular Mechanics Paths. J Chem Theory Comput 2010; 6:2948-60. [PMID: 26616091 DOI: 10.1021/ct100264j] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effects of structural fluctuations, due to protein dynamics, on enzyme activity are at the heart of current debates on enzyme catalysis. There is evidence that fatty acid amide hydrolase (FAAH) is an enzyme for which reaction proceeds via a high-energy, reactive conformation, distinct from the predominant enzyme-substrate complex (Lodola et al. Biophys. J. 2007, 92, L20-22). Identifying the structural causes of differences in reactivity between conformations in such complex systems is not trivial. Here, we show that multivariate analysis of key structural parameters can identify structural determinants of barrier height by analysis of multiple reaction paths. We apply a well-tested quantum mechanics/molecular mechanics (QM/MM) method to the first step of the acylation reaction between FAAH and oleamide substrate for 36 different starting structures. Geometrical parameters (consisting of the key bond distances that change during the reaction) were collected and used for principal component analysis (PCA), partial least-squares (PLS) regression analysis, and multiple linear regression (MLR) analysis. PCA indicates that different "families" of enzyme-substrate conformations arise from QM/MM molecular dynamics simulation and that rarely sampled, catalytically significant conformational states can be identified. PLS and MLR analyses allowed the construction of linear regression models, correlating the calculated activation barriers with simple geometrical descriptors. These analyses reveal the presence of two fully independent geometrical effects, explaining 78% of the variation in the activation barrier, which are directly correlated with transition-state stabilization (playing a major role in catalysis) and substrate binding. These results highlight the power of statistical approaches of this type in identifying crucial structural features that contribute to enzyme reactivity.
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Affiliation(s)
- Alessio Lodola
- Dipartimento Farmaceutico, Università degli Studi di Parma, 43124 Parma, Italy, and Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Jitnapa Sirirak
- Dipartimento Farmaceutico, Università degli Studi di Parma, 43124 Parma, Italy, and Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Natalie Fey
- Dipartimento Farmaceutico, Università degli Studi di Parma, 43124 Parma, Italy, and Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Silvia Rivara
- Dipartimento Farmaceutico, Università degli Studi di Parma, 43124 Parma, Italy, and Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Marco Mor
- Dipartimento Farmaceutico, Università degli Studi di Parma, 43124 Parma, Italy, and Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Adrian J Mulholland
- Dipartimento Farmaceutico, Università degli Studi di Parma, 43124 Parma, Italy, and Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
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55
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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: 356] [Impact Index Per Article: 25.4] [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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56
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Kamerlin SCL, Mavri J, Warshel A. Examining the case for the effect of barrier compression on tunneling, vibrationally enhanced catalysis, catalytic entropy and related issues. FEBS Lett 2010; 584:2759-66. [PMID: 20433839 DOI: 10.1016/j.febslet.2010.04.062] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 04/21/2010] [Accepted: 04/22/2010] [Indexed: 10/19/2022]
Abstract
The idea that tunneling is enhanced by the compression of the donor-acceptor distance has attracted significant interest. In particular, recent studies argued that this proposal is consistent with pressure effects on enzymatic reactions, and that the observed pressure effects support the idea of vibrationally enhanced catalysis. However, a careful analysis of the current works reveals serious inconsistencies in the evidence presented to support these hypotheses. Apparently, tunneling decreases upon compression, and external pressure does not lead to the applicable compression of the free energy surface. Additionally, pressure experiments do not provide actual evidence for vibrationally enhanced catalysis. Finally, the temperature dependence of the entropy change in hydride transfer reactions is shown to reflect simple electrostatic effects.
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57
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Williams IH. Quantum catalysis? A comment on tunnelling contributions for catalysed and uncatalysed reactions. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1658] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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58
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Choi SB, Normi YM, Wahab HA. Why hypothetical protein KPN00728 of Klebsiella pneumoniae should be classified as chain C of succinate dehydrogenase? Protein J 2010; 28:415-27. [PMID: 19859792 PMCID: PMC2785890 DOI: 10.1007/s10930-009-9209-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Twenty percent of genes that encode for hypothetical proteins from Klebsiella pneumoniae MGH78578 were identified, leading to KPN00728 and KPN00729 after bioinformatics analysis. Both open reading frames showed high sequence homology to Succinate dehydrogenase Chain C (SdhC) and D (SdhD) from Escherichia coli. Recently, KPN00729 was assigned as SdhD. KPN00728 thus remains of particular interest as no annotated genes from the complete genome sequence encode for SdhC. We discovered KPN00728 has a missing region with conserved residues important for ubiquinone (UQ) and heme group binding. Structure and function prediction of KPN00728 coupled with secondary structure analysis and transmembrane topology showed KPN00728 adopts SDH-(subunit C)-like structure. To further probe its functionality, UQ was docked on the built model (consisting KPN00728 and KPN00729) and formation of hydrogen bonds between UQ and Ser27, Arg31 (KPN00728) and Tyr84 (KPN00729) further reinforces and supports that KPN00728 is indeed SDH. This is the first report on the structural and function prediction of KPN00728 of K. pneumoniae MGH78578 as SdhC.
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Affiliation(s)
- Sy Bing Choi
- Pharmaceutical Design and Simulation (PhDS) Laboratory, School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang Malaysia
| | - Yahaya M. Normi
- School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang Malaysia
| | - Habibah A. Wahab
- Pharmaceutical Design and Simulation (PhDS) Laboratory, School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang Malaysia
- Centre for Advanced Drug Delivery, Malaysian Institute of Pharmaceuticals and Nutraceuticals, Ministry of Science, Technology and Innovation, SAINS@USM, No 10, 11900 Persiaran Bukit Jambul, Pulau Pinang Malaysia
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59
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Calderon CP. Detection of Subtle Dynamical Changes Induced by Unresolved “Conformational Coordinates” in Single-Molecule Trajectories via Goodness-of-Fit Tests. J Phys Chem B 2010; 114:3242-53. [DOI: 10.1021/jp911124z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher P. Calderon
- High Performance Computing Research Department, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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60
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Computer simulations of quantum tunnelling in enzyme-catalysed hydrogen transfer reactions. Interdiscip Sci 2010; 2:78-97. [DOI: 10.1007/s12539-010-0093-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 12/04/2009] [Accepted: 12/06/2009] [Indexed: 10/19/2022]
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61
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Kamerlin SCL, Warshel A. An Analysis of All the Relevant Facts and Arguments Indicates that Enzyme Catalysis Does Not Involve Large Contributions from Nuclear Tunneling. J PHYS ORG CHEM 2010; 23:677-684. [PMID: 21494414 DOI: 10.1002/poc.1620] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Shina C L Kamerlin
- Department of Chemistry, University of Southern California, 3620 McClintock Ave., Los Angeles CA-90089, USA
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62
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Mata RA. Application of high level wavefunction methods in quantum mechanics/molecular mechanics hybrid schemes. Phys Chem Chem Phys 2010; 12:5041-52. [DOI: 10.1039/b918608e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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63
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Sumner I, Iyengar SS. Analysis of Hydrogen Tunneling in an Enzyme Active Site using von Neumann Measurements. J Chem Theory Comput 2010; 6:6-10. [PMID: 22933858 PMCID: PMC3428049 DOI: 10.1021/ct900630n] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We build on our earlier quantum wavepacket study of hydrogen transfer in the biological enzyme, soybean lipoxygenase-1, by using von Neumann quantum measurement theory to gain qualitative insights into the transfer event. We treat the enzyme active site as a measurement device which acts on the tunneling hydrogen nucleus via the potential it exerts at each configuration. A series of changing active site geometries during the tunneling process effects a sequential projection of the initial, reactant state onto the final, product state. We study this process using several different kinds of von Neumann measurements and show how a discrete sequence of such measurements not only progressively increases the projection of the hydrogen nuclear wavepacket onto the product side but also favors proton over deuteron transfer. Several qualitative features of the hydrogen tunneling problem found in wavepacket dynamics studies are also recovered here. These include the shift in the "transition state" towards the reactant as a result of nuclear quantization, greater participation of excited states in the case of deuterium, and presence of critical points along the reaction coordinate that facilitate hydrogen and deuterium transfer and coincide with surface crossings. To further "tailor" the dynamics, we construct a perturbation to the sequence of measurements, that is a perturbation to the dynamical sequence of active site geometry evolution, which leads us to insight on the existence of sensitive regions of the reaction profile where subtle changes to the dynamics of the active site can have an effect on the hydrogen and deuterium transfer process.
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Affiliation(s)
- Isaiah Sumner
- Department of Chemistry and Department of Physics, Indiana University, 800 E. Kirkwood Ave, Bloomington, IN-47405
| | - Srinivasan S. Iyengar
- Department of Chemistry and Department of Physics, Indiana University, 800 E. Kirkwood Ave, Bloomington, IN-47405
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64
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Ghalla H, Rekik N, Michta A, Oujia B, Flakus HT. Theoretical modeling of infrared spectra of the hydrogen and deuterium bond in aspirin crystal. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2010; 75:37-47. [PMID: 19884041 DOI: 10.1016/j.saa.2009.09.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 09/06/2009] [Accepted: 09/13/2009] [Indexed: 05/28/2023]
Abstract
An extended quantum theoretical approach of the nu(X-H) IR lineshape of cyclic dimers of weakly H-bonded species is proposed. We have extended a previous approach [M.E.-A. Benmalti, P. Blaise, H.T. Flakus, O. Henri-Rousseau, Chem. Phys. 320 (2006) 267] by accounting for the anharmonicity of the slow mode which is described by a "Morse" potential in order to reproduce the polarized infrared spectra of the hydrogen and deuterium bond in acetylsalicylic acid (aspirin) crystals. From comparison of polarized IR spectra of isotopically neat and isotopically diluted aspirin crystals it resulted that centrosymmetric aspirin dimer was the bearer of the crystal main spectral properties. In this approach, the adiabatic approximation is performed for each separate H-bond bridge of the dimer and a strong non-adiabatic correction is introduced into the model via the resonant exchange between the fast mode excited states of the two moieties. Within the strong anharmonic coupling theory, according to which the X-H...Y high-frequency mode is anharmonically coupled to the H-bond bridge, this model incorporated the Davydov coupling between the excited states of the two moieties, the quantum direct and indirect dampings and the anharmonicity for the H-bond bridge. The spectral density is obtained within the linear response theory by Fourier transform of the damped autocorrelation functions. The evaluated spectra are in fairly good agreement with the experimental ones by using a minimum number of independent parameters. The effect of deuteration has been well reproduced by reducing simply the angular frequency of the fast mode and the anharmonic coupling parameter.
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Affiliation(s)
- Houcine Ghalla
- Laboratoire de Physique Quantique, Faculté des Sciences de Monastir, 5000 route de Kairouan, Tunisia
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65
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66
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Rekik N, Ghalla H, Flakus HT, JabÅonÌska M, Blaise P, Oujia B. Polarized Infrared Spectra of the H(D) Bond in 2-Thiophenic Acid Crystals: A Spectroscopic and Computational Study. Chemphyschem 2009; 10:3021-33. [DOI: 10.1002/cphc.200900376] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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67
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Baron R, McCammon JA, Mattevi A. The oxygen-binding vs. oxygen-consuming paradigm in biocatalysis: structural biology and biomolecular simulation. Curr Opin Struct Biol 2009; 19:672-9. [DOI: 10.1016/j.sbi.2009.10.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 10/07/2009] [Indexed: 11/28/2022]
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68
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Pierdominici-Sottile G, Palma J. Evaluation of the kinetic isotope effect in methylamine dehydrogenase using the wave function propagation approach. Chem Phys 2009. [DOI: 10.1016/j.chemphys.2009.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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69
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Sabolović J, Gomzi V. Structure Prediction of Bis(amino acidato)copper(II) Complexes with a New Force Field for Molecular Modeling. J Chem Theory Comput 2009; 5:1940-54. [DOI: 10.1021/ct9000203] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Jasmina Sabolović
- Institute for Medical Research and Occupational Health, Ksaverska cesta 2, P.O. Box 291, HR-10001 Zagreb, Croatia, and Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia
| | - Vjeran Gomzi
- Institute for Medical Research and Occupational Health, Ksaverska cesta 2, P.O. Box 291, HR-10001 Zagreb, Croatia, and Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia
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70
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Hay S, Sutcliffe MJ, Scrutton NS. Probing Coupled Motions in Enzymatic Hydrogen Tunnelling Reactions: Beyond Temperature-Dependence Studies of Kinetic Isotope Effects. QUANTUM TUNNELLING IN ENZYME-CATALYSED REACTIONS 2009. [DOI: 10.1039/9781847559975-00199] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Sam Hay
- Faculty of Life Sciences, Manchester Interdisciplinary Biocentre, University of Manchester 131 Princess Street Manchester M1 7DN UK
| | - Michael J. Sutcliffe
- School of Chemical Engineering and Analytical Science, Manchester Interdisciplinary Biocentre, University of Manchester 131 Princess Street Manchester M1 7DN UK
| | - Nigel S. Scrutton
- Faculty of Life Sciences, Manchester Interdisciplinary Biocentre, University of Manchester 131 Princess Street Manchester M1 7DN UK
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71
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Abstract
Combined quantum-mechanics/molecular-mechanics (QM/MM) approaches have become the method of choice for modeling reactions in biomolecular systems. Quantum-mechanical (QM) methods are required for describing chemical reactions and other electronic processes, such as charge transfer or electronic excitation. However, QM methods are restricted to systems of up to a few hundred atoms. However, the size and conformational complexity of biopolymers calls for methods capable of treating up to several 100,000 atoms and allowing for simulations over time scales of tens of nanoseconds. This is achieved by highly efficient, force-field-based molecular mechanics (MM) methods. Thus to model large biomolecules the logical approach is to combine the two techniques and to use a QM method for the chemically active region (e.g., substrates and co-factors in an enzymatic reaction) and an MM treatment for the surroundings (e.g., protein and solvent). The resulting schemes are commonly referred to as combined or hybrid QM/MM methods. They enable the modeling of reactive biomolecular systems at a reasonable computational effort while providing the necessary accuracy.
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Affiliation(s)
- Hans Martin Senn
- Department of Chemistry, WestCHEM and University of Glasgow, Glasgow G12 8QQ, UK.
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72
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Barroso M, Arnaut LG, Formosinho SJ. The role of reaction energy and hydrogen bonding in the reaction path of enzymatic proton transfers. J PHYS ORG CHEM 2009. [DOI: 10.1002/poc.1463] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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73
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74
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Johannissen LO, Scrutton NS, Sutcliffe MJ. The enzyme aromatic amine dehydrogenase induces a substrate conformation crucial for promoting vibration that significantly reduces the effective potential energy barrier to proton transfer. J R Soc Interface 2009; 5 Suppl 3:S225-32. [PMID: 18495615 DOI: 10.1098/rsif.2008.0068.focus] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The role of promoting vibrations in enzymic reactions involving hydrogen tunnelling is contentious. While models incorporating such promoting vibrations have successfully reproduced and explained experimental observations, it has also been argued that such vibrations are not part of the catalytic effect. In this study, we have employed combined quantum mechanical/molecular mechanical methods with molecular dynamics and potential energy surface calculations to investigate how enzyme and substrate motion affects the energy barrier to proton transfer for the rate-limiting H-transfer step in aromatic amine dehydrogenase (AADH) with tryptamine as substrate. In particular, the conformation of the iminoquinone adduct induced by AADH was found to be essential for a promoting vibration identified previously-this lowers significantly the 'effective' potential energy barrier, that is the barrier which remains to be surmounted following collective, thermally equilibrated motion attaining a quantum degenerate state of reactants and products. When the substrate adopts a conformation similar to that in the free iminoquinone, this barrier was found to increase markedly. This is consistent with AADH facilitating the H-transfer event by holding the substrate in a conformation that induces a promoting vibration.
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Affiliation(s)
- Linus O Johannissen
- School of Chemical Engineering and Analytical Science and Manchester Interdisciplinary Biocentre, University of Manchester, 131 Princess Street, Manchester, UK
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75
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Abstract
'Everything that living things do can be understood in terms of the jigglings and wigglings of atoms' as Richard Feynman provocatively stated nearly 50 years ago. But how can we 'see' this wiggling and jiggling and understand how it drives biology? Increasingly, computer simulations of biological macromolecules are helping to meet this challenge.
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Affiliation(s)
- Adrian J Mulholland
- School of Chemistry, Centre for Computational Chemistry, University of Bristol, Bristol, UK.
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76
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Hay S, Pang J, Monaghan PJ, Wang X, Evans RM, Sutcliffe MJ, Allemann RK, Scrutton NS. Secondary kinetic isotope effects as probes of environmentally-coupled enzymatic hydrogen tunneling reactions. Chemphyschem 2008; 9:1536-9. [PMID: 18613201 DOI: 10.1002/cphc.200800291] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sam Hay
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
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77
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Barroso M, Arnaut LG, Formosinho SJ. A chemical understanding for the enhanced hydrogen tunnelling in hydroperoxidation of linoleic acid catalysed by soybean lipoxygenase-1. J PHYS ORG CHEM 2008. [DOI: 10.1002/poc.1346] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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78
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Mavri J, Liu H, Olsson MHM, Warshel A. Simulation of tunneling in enzyme catalysis by combining a biased propagation approach and the quantum classical path method: application to lipoxygenase. J Phys Chem B 2008; 112:5950-4. [PMID: 18069813 DOI: 10.1021/jp0758420] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The ability of using wave function propagation approaches to simulate isotope effects in enzymes is explored, focusing on the large H/D kinetic isotope effect of soybean lipoxygenase-1 (SLO-1). The H/D kinetic isotope effect (KIE) is calculated as the ratio of the rate constants for hydrogen and deuterium transfer. The rate constants are calculated from the time course of the H and D nuclear wave functions. The propagations are done using one-dimensional proton potentials generated as sections from the full multidimensional surface of the reacting system in the protein. The sections are obtained during a classical empirical valence bond (EVB) molecular dynamics simulation of SLO-1. Since the propagations require an extremely long time for treating realistic activation barriers, it is essential to use an effective biasing approach. Thus, we develop here an approach that uses the classical quantum path (QCP) method to evaluate the quantum free energy change associated with the biasing potential. This approach provides an interesting alternative to full QCP simulations and to other current approaches for simulating isotope effects in proteins. In particular, this approach can be used to evaluate the quantum mechanical transmission factor or other dynamical effects, while still obtaining reliable quantized activation free energies due to the QCP correction.
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Affiliation(s)
- Janez Mavri
- National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
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79
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Hay S, Pudney CR, Sutcliffe MJ, Scrutton NS. Are environmentally coupled enzymatic hydrogen tunneling reactions influenced by changes in solution viscosity? Angew Chem Int Ed Engl 2008; 47:537-40. [PMID: 18058788 DOI: 10.1002/anie.200704484] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Sam Hay
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
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80
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Hay S, Pudney C, Sutcliffe M, Scrutton N. Are Environmentally Coupled Enzymatic Hydrogen Tunneling Reactions Influenced by Changes in Solution Viscosity? Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200704484] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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81
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Ranaghan KE, Masgrau L, Scrutton NS, Sutcliffe MJ, Mulholland AJ. Analysis of Classical and Quantum Paths for Deprotonation of Methylamine by Methylamine Dehydrogenase. Chemphyschem 2007; 8:1816-35. [PMID: 17676581 DOI: 10.1002/cphc.200700143] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The hydrogen-transfer reaction catalysed by methylamine dehydrogenase (MADH) with methylamine (MA) as substrate is a good model system for studies of proton tunnelling in enzyme reactions--an area of great current interest--for which atomistic simulations will be vital. Here, we present a detailed analysis of the key deprotonation step of the MADH/MA reaction and compare the results with experimental observations. Moreover, we compare this reaction with the related aromatic amine dehydrogenase (AADH) reaction with tryptamine, recently studied by us, and identify possible causes for the differences observed in the measured kinetic isotope effects (KIEs) of the two systems. We have used combined quantum mechanics/molecular mechanics (QM/MM) techniques in molecular dynamics simulations and variational transition state theory with multidimensional tunnelling calculations averaged over an ensemble of paths. The results reveal important mechanistic complexity. We calculate activation barriers and KIEs for the two possible proton transfers identified-to either of the carboxylate oxygen atoms of the catalytic base (Asp428beta)-and analyse the contributions of quantum effects. The activation barriers and tunnelling contributions for the two possible proton transfers are similar and lead to a phenomenological activation free energy of 16.5+/-0.9 kcal mol(-1) for transfer to either oxygen (PM3-CHARMM calculations applying PM3-SRP specific reaction parameters), in good agreement with the experimental value of 14.4 kcal mol(-1). In contrast, for the AADH system, transfer to the equivalent OD1 was found to be preferred. The structures of the enzyme complexes during reaction are analysed in detail. The hydrogen bond of Thr474beta(MADH)/Thr172beta(AADH) to the catalytic carboxylate group and the nonconserved active site residue Tyr471beta(MADH)/Phe169beta(AADH) are identified as important factors in determining the preferred oxygen acceptor. The protein environment has a significant effect on the reaction energetics and hence on tunnelling contributions and KIEs. These environmental effects, and the related clearly different preferences for the two carboxylate oxygen atoms (with different KIEs) in MADH/MA and AADH/tryptamine, are possible causes of the differences observed in the KIEs between these two important enzyme reactions.
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Affiliation(s)
- Kara E Ranaghan
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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82
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Jezierska A, Panek JJ, Koll A, Mavri J. Car-Parrinello simulation of an O-H stretching envelope and potential of mean force of an intramolecular hydrogen bonded system: application to a Mannich base in solid state and in vacuum. J Chem Phys 2007; 126:205101. [PMID: 17552801 DOI: 10.1063/1.2736692] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Car-Parrinello molecular dynamics (CPMD) study was performed for an anharmonic system-an intramolecularly hydrogen bonded Mannich-base-type compound, 4,5-dimethyl-2(N,N-dimethylaminemethyl)phenol, to investigate the vibrational spectrum associated with the O-H stretching. Calculations were carried out for the solid state and for an isolated molecule. The classical CPMD simulation was performed and then the proton potential snapshots were extracted from the trajectory. The vibrational Schrodinger equation for the snapshots was solved numerically, and the (O-H) envelope was calculated as a superposition of the 0-->1 transitions. The potential of mean force for the proton stretching mode was calculated from the proton vibrational eigenfunctions and eigenvalues incorporating statistical sampling, nuclear quantum effects, and effects of the environment. Perspectives for application of the presented methodology in the computational support of biocatalysis are given in the study.
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Affiliation(s)
- Aneta Jezierska
- Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie, 50-383 Wroclaw, Poland
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83
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Liu H, Warshel A. Origin of the Temperature Dependence of Isotope Effects in Enzymatic Reactions: The Case of Dihydrofolate Reductase. J Phys Chem B 2007; 111:7852-61. [PMID: 17571875 DOI: 10.1021/jp070938f] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The origin of the temperature dependence of kinetic isotope effects (KIEs) in enzyme reactions is a problem of general interest and a major challenge for computational chemistry. The present work simulates the nuclear quantum mechanical (NQM) effects and the corresponding KIE in dihydrofolate reductase (DHFR) and two of its mutants by using the empirical valence bond (EVB) and the quantum classical path (QCP) centroid path integral approach. Our simulations reproduce the overall observed trend while using a fully microscopic rather than a phenomenological picture and provide an interesting insight. It appears that the KIE increases when the distance between the donor and acceptor increases, in a somewhat counter intuitive way. The temperature dependence of the KIE appears to reflect mainly the temperature dependence of the distance between the donor and acceptor. This trend is also obtained from a simplified vibronic treatment, but as demonstrated here, the vibronic treatment is not valid at short and medium distances, where it is essential to use the path integral or other approaches capable of moving seamlessly from the adiabatic to the diabatic limits. It is pointed out that although the NQM effects do not contribute to catalysis in DHFR, the observed temperature dependence can be used to refine the potential of mean force for the donor and acceptor distance and its change due to distanced mutations.
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Affiliation(s)
- Hanbin Liu
- Department of Chemistry, University of Southern California, 3620 McClintock Avenue, Los Angeles, California 90089-1062, USA
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84
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Marcus RA. H and other transfers in enzymes and in solution: theory and computations, a unified view. 2. Applications to experiment and computations. J Phys Chem B 2007; 111:6643-54. [PMID: 17497918 DOI: 10.1021/jp071589s] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Equations obtained in part I for the free-energy barrier to one-step enzymatic reactions between bound reactants are discussed. The rate is expressed in terms of lambdao (protein reorganization energy), DeltaG(o) (standard free energy of reaction of the H-transfer step), bond breaking/bond forming term, w (work terms), and H-transmission property. Two alternative approximations for the coupling of the bond breaking/bond forming and protein are distinguished experimentally in favorable cases by the DeltaG(o) where the maximum deuterium kinetic isotope effect occurs. Plots of log rate versus DeltaG(o) and properties such as DeltaS* and DeltaS(o) are discussed. The weak or zero T-dependence of the kinetic isotope effect for wild-type enzymes operating under physiological conditions is interpreted in terms of vanishing (or isotopically insensitive) w plus transfer from the lowest H-state. Static and dynamic protein flexibility is discussed. While the many correlations accessible for electron transfers are not available for H-transfers in enzymes, a combination of experiment, computation, and analytical approaches can assist in evaluating the utility of the present equations and in suggesting further experiments and computations. A protein reorganization energy lambdao is obtained in the literature from the extended valence bond formalism where diabatic electronic states are used. A method is suggested for extracting it when instead a bond distance difference coordinate is used. The results may provide a bridge between the two approaches.
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Affiliation(s)
- R A Marcus
- Noyes Laboratory of Chemical Physics, MC 127-72, California Institute of Technology, Pasadena, California 91125-0072, USA.
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85
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Boiteux C, Kraszewski S, Ramseyer C, Girardet C. Ion conductance vs. pore gating and selectivity in KcsA channel: Modeling achievements and perspectives. J Mol Model 2007; 13:699-713. [PMID: 17415597 DOI: 10.1007/s00894-007-0202-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Revised: 03/08/2007] [Accepted: 03/19/2007] [Indexed: 12/29/2022]
Abstract
KcsA potassium channel belongs to a wide family of allosteric proteins that switch between closed and open states conformations in response to a stimulus, and act as a regulator of cation activity in living cells. The gating mechanism and cation selectivity of such channels have been extensively studied in the literature, with a revival emphasis these latter years, due to the publication of the crystallized structure of KcsA. Despite the increasing number of research and review papers on these topics, quantitative interpretation of these processes at the atomic scale is far from achieved. On the basis of available experimental and theoretical data, and by including our recent results, we review the progresses in this field of activity and discuss the weaknesses that should be corrected. In this spirit, we partition the channel into the filter, cavity, extra and intracellular media, in order to analyze separately the specificity of each region. Special emphasis is brought to the study of an open state for the channel and to the different properties generated by the opening. The influence of water as a structural and dynamical component of the channel properties in closed and open states, as well as in the sequential motions of the cations, is analyzed using molecular dynamics simulations and ab initio calculations. The polarization and charge transfer effects on the ions' dynamics and kinetics are discussed in terms of partial charge models.
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Affiliation(s)
- Céline Boiteux
- Laboratoire de Physique Moléculaire UMR CNRS 6624, Université de Franche-Comté, La Bouloie, 25030, Besançon Cedex, France
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86
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Masgrau L, Ranaghan KE, Scrutton NS, Mulholland AJ, Sutcliffe MJ. Tunneling and Classical Paths for Proton Transfer in an Enzyme Reaction Dominated by Tunneling: Oxidation of Tryptamine by Aromatic Amine Dehydrogenase. J Phys Chem B 2007; 111:3032-47. [PMID: 17388439 DOI: 10.1021/jp067898k] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Proton tunneling dominates the oxidative deamination of tryptamine catalyzed by the enzyme aromatic amine dehydrogenase. For reaction with the fast substrate tryptamine, a H/D kinetic isotope effect (KIE) of 55 +/- 6 has been reported-one of the largest observed in an enzyme reaction. We present here a computational analysis of this proton-transfer reaction, applying combined quantum mechanics/molecular mechanics (QM/MM) methods (PM3-SRP//PM3/CHARMM22). In particular, we extend our previous computational study (Masgrau et al. Science 2006, 312, 237) by using improved energy corrections, high-level QM/MM methods, and an ensemble of paths to estimate the tunneling contributions. We have carried out QM/MM molecular dynamics simulations and variational transition state theory calculations with small-curvature tunneling corrections. The results provide detailed insight into the processes involved in the reaction. Transfer to the O2 oxygen of the catalytic base, Asp128beta, is found to be the favored reaction both thermodynamically and kinetically, even though O1 is closer in the reactant complex. Comparison of quantum and classical models of proton transfer allows estimation of the contribution of hydrogen tunneling in lowering the barrier to reaction in the enzyme. A reduction of the activation free energy due to tunneling of 3.1 kcal mol-1 is found, which represents a rate enhancement due to tunneling by 2 orders of magnitude. The calculated KIE of 30 is significantly elevated over the semiclassical limit, in agreement with the experimental observations; a semiclassical value of 6 is obtained when tunneling is omitted. A polarization of the C-H bond to be broken is observed due to the close proximity of the catalytic aspartate and the (formally) positively charged imine nitrogen. A comparison is also made with the related quinoprotein methylamine dehydrogenase (MADH)-the much lower KIE of 11 that we obtain for the MADH/methylamine system is found to arise from a more endothermic potential energy surface for the MADH reaction.
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Affiliation(s)
- Laura Masgrau
- Manchester Interdisciplinary Biocentre, School of Chemical Engineering and Analytical Science, and Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
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87
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Dutton PL, Munro AW, Scrutton NS, Sutcliffe MJ. Introduction. Quantum catalysis in enzymes: beyond the transition state theory paradigm. Philos Trans R Soc Lond B Biol Sci 2006. [DOI: 10.1098/rstb.2006.1879] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- P. Leslie Dutton
- Department of Biochemistry and Biophysics, University of PennsylvaniaPhiladelphia, PA 19104-6059, USA
| | - Andrew W Munro
- Manchester Interdisciplinary Biocentre, University of Manchester131 Princess Street, Manchester M1 7ND, UK
- School of Chemical Engineering and Analytical Science, University of Manchester131 Princess Street, Manchester M1 7ND, UK
| | - Nigel S Scrutton
- Faculty of Life Sciences, University of Manchester131 Princess Street, Manchester M1 7ND, UK
| | - Michael J Sutcliffe
- Manchester Interdisciplinary Biocentre, University of Manchester131 Princess Street, Manchester M1 7ND, UK
- School of Chemical Engineering and Analytical Science, University of Manchester131 Princess Street, Manchester M1 7ND, UK
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