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Vealey ZN, Foguel L, Vaccaro PH. Hydrogen-Bonding Motifs and Proton-Transfer Dynamics in Electronically Excited 6-Hydroxy-2-formylfulvene. J Phys Chem A 2019; 123:6506-6526. [DOI: 10.1021/acs.jpca.9b05025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zachary N. Vealey
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, United States
| | - Lidor Foguel
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, United States
| | - Patrick H. Vaccaro
- Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, United States
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2
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Lima MCP, Seabra GM. Reaction mechanism of the dengue virus serine protease: a QM/MM study. Phys Chem Chem Phys 2018; 18:30288-30296. [PMID: 27341353 DOI: 10.1039/c6cp03209e] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dengue virus (DENV) is the causative agent of the viral infection dengue fever. In spite of all the efforts made to prevent the spread of the disease, once it is contracted, there is no specific treatment for dengue and the WHO guidelines are limited to rest and symptomatic treatment. In its reproductive cycle, DENV utilizes the NS2B-NS3pro, a serine protease, to cleave the viral polyprotein into its constituents. This enzyme is essential for the virus lifecycle, and presents an attractive target for the development of specific dengue treatments. Here we used a hybrid Quantum Mechanics and Molecular Mechanics (QM/MM) Molecular Dynamics approach and Umbrella Sampling to study the first step (acylation) of the reaction catalyzed by NS2B-NS3pro, using the Pairwise Distance Directed Gaussian PM3 (PDDG/PM3) semi-empirical Hamiltonian for the QM subsystem, and Amber ff99SB for the MM subsystem. Our results indicate that the nucleophilic attack on the substrate by Ser135 occurs in a stepwise manner, in which a proton transfer to His51 first activates Ser135, which only later attacks the substrate. The rate-determining step is the Ser135 activation, with a barrier of 24.1 kcal mol-1. Water molecules completing the oxyanion hole stabilize the negative charge formed on the carbonyl oxygen of the substrate. The final step in the process is a proton transfer from His51 to the substrate's nitrogen, which happens with a lower barrier of 5.1 kcal mol-1, and leads directly to the breakage of the peptide bond.
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Affiliation(s)
- M C P Lima
- Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, Av. Jornalista Anibal Fernandes, s/no, Cidade Universitária - Recife, PE - CEP 50.740-560, Brazil.
| | - G M Seabra
- Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, Av. Jornalista Anibal Fernandes, s/no, Cidade Universitária - Recife, PE - CEP 50.740-560, Brazil.
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3
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Kale S, Sode O, Weare J, Dinner AR. Finding Chemical Reaction Paths with a Multilevel Preconditioning Protocol. J Chem Theory Comput 2014; 10:5467-5475. [PMID: 25516726 PMCID: PMC4263463 DOI: 10.1021/ct500852y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Indexed: 11/28/2022]
Abstract
Finding transition paths for chemical reactions can be computationally costly owing to the level of quantum-chemical theory needed for accuracy. Here, we show that a multilevel preconditioning scheme that was recently introduced (Tempkin et al. J. Chem. Phys.2014, 140, 184114) can be used to accelerate quantum-chemical string calculations. We demonstrate the method by finding minimum-energy paths for two well-characterized reactions: tautomerization of malonaldehyde and Claissen rearrangement of chorismate to prephanate. For these reactions, we show that preconditioning density functional theory (DFT) with a semiempirical method reduces the computational cost for reaching a converged path that is an optimum under DFT by several fold. The approach also shows promise for free energy calculations when thermal noise can be controlled.
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Affiliation(s)
- Seyit Kale
- Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States ; Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States
| | - Olaseni Sode
- Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States ; Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States ; Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States ; Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States ; Computing, Environment, and Life Sciences, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Jonathan Weare
- Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States ; Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States ; Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States
| | - Aaron R Dinner
- Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States ; Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States ; Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States ; Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, Department of Statistics, University of Chicago , Chicago, Illinois 60637, United States
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7
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Seabra GDM, Walker RC, Roitberg AE. Are current semiempirical methods better than force fields? A study from the thermodynamics perspective. J Phys Chem A 2010; 113:11938-48. [PMID: 19848431 DOI: 10.1021/jp903474v] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The semiempirical Hamiltonians MNDO, AM1, PM3, RM1, PDDG/MNDO, PDDG/PM3, and SCC-DFTB, when used as part of a hybrid QM/MM scheme for the simulation of biological molecules, were compared on their abilities to reproduce experimental ensemble averages at or near room temperatures for the model system alanine dipeptide in water. Free energy surfaces in the (phi, psi) dihedral angle space, (3)J(H(N),H(alpha)) NMR dipolar coupling constants, basin populations, and peptide-water radial distribution functions (RDF) were calculated from replica exchange simulations and compared to both experiment and fully classical force field calculations using the Amber ff99SB force field. In contrast with the computational chemist's intuitive idea that the more expensive a method the better its accuracy, the ff99SB force field results were more accurate than most of the semiempirical methods, with the exception of RM1. None of the methods, however, was able to accurately reproduce the experimental data. Analysis of the results indicate that the specific QM/MM interactions have little influence on the sampling of free energy surfaces, and the differences are well explained simply by the intrinsic properties of the various QM methods.
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Affiliation(s)
- Gustavo de M Seabra
- Quantum Theory Project and Department of Chemistry, University of Florida, 2234 New Physics Building #92, P.O. Box 118435, Gainesville, Florida 32611-8435, USA
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Bondar AN, Suhai S, Fischer S, Smith JC, Elstner M. Suppression of the back proton-transfer from Asp85 to the retinal Schiff base in bacteriorhodopsin: A theoretical analysis of structural elements. J Struct Biol 2007; 157:454-69. [PMID: 17189704 DOI: 10.1016/j.jsb.2006.10.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Revised: 09/26/2006] [Accepted: 10/03/2006] [Indexed: 11/15/2022]
Abstract
The transfer of a proton from the retinal Schiff base to the nearby Asp85 protein group is an essential step in the directional proton-pumping by bacteriorhodopsin. To avoid the wasteful back reprotonation of the Schiff base from Asp85, the protein must ensure that, following Schiff base deprotonation, the energy barrier for back proton-transfer from Asp85 to the Schiff base is larger than that for proton-transfer from the Schiff base to Asp85. Here, three structural elements that may contribute to suppressing the back proton-transfer from Asp85 to the Schiff base are investigated: (i) retinal twisting; (ii) hydrogen-bonding distances in the active site; and (iii) the number and location of internal water molecules. The impact of the pattern of bond twisting on the retinal deprotonation energy is dissected by performing an extensive set of quantum-mechanical calculations. Structural rearrangements in the active site, such as changes of the Thr89:Asp85 distance and relocation of water molecules hydrogen-bonding to the Asp85 acceptor group, may participate in the mechanism which ensures that following the transfer of the Schiff base proton to Asp85 the protein proceeds with the subsequent photocycle steps, and not with back proton transfer from Asp85 to the Schiff base.
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Affiliation(s)
- Ana-Nicoleta Bondar
- Computational Molecular Biophysics, IWR, University of Heidelberg, Im Neuenheimer Feld 368, 69120 Heidelberg, Germany
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Meroueh SO, Wang Y, Hase WL. Direct Dynamics Simulations of Collision- and Surface-Induced Dissociation of N-Protonated Glycine. Shattering Fragmentation. J Phys Chem A 2002. [DOI: 10.1021/jp020664q] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Samy O. Meroueh
- Department of Chemistry and Institute for Scientific Computing, Wayne State University, Detroit, Michigan 48202-3489
| | - Yanfei Wang
- Department of Chemistry and Institute for Scientific Computing, Wayne State University, Detroit, Michigan 48202-3489
| | - William L. Hase
- Department of Chemistry and Institute for Scientific Computing, Wayne State University, Detroit, Michigan 48202-3489
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Perrin CL, Ohta BK. Symmetry of O-H-O and N-H-N hydrogen bonds in 6-hydroxy-2-formylfulvene and 6-aminofulvene-2-aldimines. Bioorg Chem 2002; 30:3-15. [PMID: 11954999 DOI: 10.1006/bioo.2001.1222] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The symmetry of the hydrogen bonds in 6-hydroxy-2-formylfulvene and two N,N'-diaryl-6-aminofulvene-2-aldimines is probed by the NMR technique of isotopic perturbation. Observed deuterium-induced 13C NMR isotope shifts at several positions can be attributed to a combination of an intrinsic shift and the perturbation of a tautomeric equilibrium. The most dramatic are at the aldehydic or aldiminic carbon signals, where the observed isotope shift for the unlabeled carbon is +376 or +223 ppb. This large downfield shift is contrary to the small upfield shift expected for a four-bond intrinsic shift and can be attributed only to a perturbation shift. Therefore these intramolecular hydrogen bonds are asymmetric, the proton resides in a double-minimum potential surface, and each molecule exists as a pair of rapidly interconverting tautomers, regardless of solvent. The symmetry of the hydrogen bond is not governed only by the O-O or N-N distance. It is proposed that symmetric hydrogen bonds can be observed in crystalline phases but not as yet in solution because the disorder of the solvation environment induces an asymmetry of the hydrogen bond, whereas a crystal can guarantee a symmetric environment. These results provide no insight into the source of the stabilization attributed to low-barrier hydrogen bonds if they lack the special feature of symmetry.
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Affiliation(s)
- Charles L Perrin
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla 92093-0358, USA.
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