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Han Du WG, Götz AW, Noodleman L. A Water Dimer Shift Activates a Proton Pumping Pathway in the P R → F Transition of ba 3 Cytochrome c Oxidase. Inorg Chem 2018; 57:1048-1059. [PMID: 29308889 DOI: 10.1021/acs.inorgchem.7b02461] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Broken-symmetry density functional calculations have been performed on the [Fea34+,CuB2+] state of the dinuclear center (DNC) for the PR → F part of the catalytic cycle of ba3 cytochrome c oxidase (CcO) from Thermus thermophilus (Tt), using the OLYP-D3-BJ functional. The calculations show that the movement of the H2O molecules in the DNC affects the pKa values of the residue side chains of Tyr237 and His376+, which are crucial for proton transfer/pumping in ba3 CcO from Tt. The calculated lowest energy structure of the DNC in the [Fea34+,CuB2+] state (state F) is of the form Fea34+═O2-···CuB2+, in which the H2O ligand that resulted from protonation of the OH- ligand in the PR state is dissociated from the CuB2+ site. The calculated Fea34+═O2- distance in F (1.68 Å) is 0.03 Å longer than that in PR (1.65 Å), which can explain the different Fea34+═O2- stretching modes in P (804 cm-1) and F (785 cm-1) identified by resonance Raman experiments. In this F state, the CuB2+···O2- (ferryl-oxygen) distance is only around 2.4 Å. Hence, the subsequent OH state [Fea33+-OH--CuB2+] with a μ-hydroxo bridge can be easily formed, as shown by our calculations.
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Hirshberg B, Rossich Molina E, Götz AW, Hammerich AD, Nathanson GM, Bertram TH, Johnson MA, Gerber RB. N2O5at water surfaces: binding forces, charge separation, energy accommodation and atmospheric implications. Phys Chem Chem Phys 2018; 20:17961-17976. [DOI: 10.1039/c8cp03022g] [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
Studying the interactions between N2O5and water in nano-sized clusters, in bulk and on the surface of water.
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Riera M, Mardirossian N, Bajaj P, Götz AW, Paesani F. Toward chemical accuracy in the description of ion–water interactions through many-body representations. Alkali-water dimer potential energy surfaces. J Chem Phys 2017; 147:161715. [DOI: 10.1063/1.4993213] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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29
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Pirojsirikul T, Götz AW, Weare J, Walker RC, Kowalski K, Valiev M. Combined quantum-mechanical molecular mechanics calculations with NWChem and AMBER: Excited state properties of green fluorescent protein chromophore analogue in aqueous solution. J Comput Chem 2017; 38:1631-1639. [PMID: 28470855 DOI: 10.1002/jcc.24804] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/19/2017] [Indexed: 11/07/2022]
Abstract
Combined quantum mechanical molecular mechanics (QM/MM) calculations have become a popular methodology for efficient and accurate description of large molecular systems. In this work we introduce our development of a QM/MM framework based on two well-known codes-NWChem and AMBER. As an initial application area we are focused on excited state properties of small molecules in an aqueous phase using an analogue of the green fluorescent protein (GFP) chromophore as a particular test case. Our approach incorporates high level coupled cluster theory for the analysis of excited states providing a reliable theoretical analysis of effects of an aqueous solvation environment on the photochemical properties of the GFP chromophore. Using a systematic approach, which involves comparison of gas phase and aqueous phase results for different protonation states and conformations, we resolve existing uncertainties regarding the theoretical interpretation of experimental data. We observe that the impact of aqueous environment on charged states generally results in blue shifts of the absorption spectra, but the magnitude of the effect is sensitive to both protonation state and conformation and can be rationalized based on charge movement into the area of higher/lower external electrostatic potentials. At neutral pH levels the experimentally observed absorption signal is most likely coming from the phenol protonated form. Our results also show that the high level electron correlated method is essential for a proper description of excited states of GFP. © 2017 Wiley Periodicals, Inc.
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Steinmann SN, Fleurat‐Lessard P, Götz AW, Michel C, Ferreira de Morais R, Sautet P. Molecular mechanics models for the image charge, a comment on “including image charge effects in the molecular dynamics simulations of molecules on metal surfaces”. J Comput Chem 2017; 38:2127-2129. [DOI: 10.1002/jcc.24861] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 05/15/2017] [Indexed: 11/06/2022]
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Brown SE, Götz AW, Cheng X, Steele RP, Mandelshtam VA, Paesani F. Monitoring Water Clusters “Melt” Through Vibrational Spectroscopy. J Am Chem Soc 2017; 139:7082-7088. [DOI: 10.1021/jacs.7b03143] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Anderson JSM, Rodríguez JI, Ayers PW, Götz AW. Relativistic (SR-ZORA) quantum theory of atoms in molecules properties. J Comput Chem 2017; 38:81-86. [PMID: 27862042 DOI: 10.1002/jcc.24520] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 09/29/2016] [Accepted: 10/03/2016] [Indexed: 11/07/2022]
Abstract
The Quantum Theory of Atoms in Molecules (QTAIM) is used to elucidate the effects of relativity on chemical systems. To do this, molecules are studied using density-functional theory at both the nonrelativistic level and using the scalar relativistic zeroth-order regular approximation. Relativistic effects on the QTAIM properties and topology of the electron density can be significant for chemical systems with heavy atoms. It is important, therefore, to use the appropriate relativistic treatment of QTAIM (Anderson and Ayers, J. Phys. Chem. 2009, 115, 13001) when treating systems with heavy atoms. © 2016 Wiley Periodicals, Inc.
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Schlüns D, Franchini M, Götz AW, Neugebauer J, Jacob CR, Visscher L. Analytical gradients for subsystem density functional theory within the slater-function-based amsterdam density functional program. J Comput Chem 2016; 38:238-249. [DOI: 10.1002/jcc.24670] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 10/14/2016] [Accepted: 10/19/2016] [Indexed: 11/09/2022]
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34
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Reddy SK, Straight SC, Bajaj P, Huy Pham C, Riera M, Moberg DR, Morales MA, Knight C, Götz AW, Paesani F. On the accuracy of the MB-pol many-body potential for water: Interaction energies, vibrational frequencies, and classical thermodynamic and dynamical properties from clusters to liquid water and ice. J Chem Phys 2016; 145:194504. [DOI: 10.1063/1.4967719] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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35
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Yang L, Skjevik ÅA, Han Du WG, Noodleman L, Walker RC, Götz AW. Water exit pathways and proton pumping mechanism in B-type cytochrome c oxidase from molecular dynamics simulations. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1857:1594-1606. [PMID: 27317965 PMCID: PMC4995112 DOI: 10.1016/j.bbabio.2016.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 05/21/2016] [Accepted: 06/14/2016] [Indexed: 01/22/2023]
Abstract
Cytochrome c oxidase (CcO) is a vital enzyme that catalyzes the reduction of molecular oxygen to water and pumps protons across mitochondrial and bacterial membranes. While proton uptake channels as well as water exit channels have been identified for A-type CcOs, the means by which water and protons exit B-type CcOs remain unclear. In this work, we investigate potential mechanisms for proton transport above the dinuclear center (DNC) in ba3-type CcO of Thermus thermophilus. Using long-time scale, all-atom molecular dynamics (MD) simulations for several relevant protonation states, we identify a potential mechanism for proton transport that involves propionate A of the active site heme a3 and residues Asp372, His376 and Glu126(II), with residue His376 acting as the proton-loading site. The proposed proton transport process involves a rotation of residue His376 and is in line with experimental findings. We also demonstrate how the strength of the salt bridge between residues Arg225 and Asp287 depends on the protonation state and that this salt bridge is unlikely to act as a simple electrostatic gate that prevents proton backflow. We identify two water exit pathways that connect the water pool above the DNC to the outer P-side of the membrane, which can potentially also act as proton exit transport pathways. Importantly, these water exit pathways can be blocked by narrowing the entrance channel between residues Gln151(II) and Arg449/Arg450 or by obstructing the entrance through a conformational change of residue Tyr136, respectively, both of which seem to be affected by protonation of residue His376.
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Yamamoto T, Tsigelny IF, Götz AW, Howell SB. Cisplatin inhibits MEK1/2. Oncotarget 2016; 6:23510-22. [PMID: 26155939 PMCID: PMC4695133 DOI: 10.18632/oncotarget.4355] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 06/09/2015] [Indexed: 11/30/2022] Open
Abstract
Cisplatin (cDDP) is known to bind to the CXXC motif of proteins containing a ferrodoxin-like fold but little is known about its ability to interact with other Cu-binding proteins. MEK1/2 has recently been identified as a Cu-dependent enzyme that does not contain a CXXC motif. We found that cDDP bound to and inhibited the activity of recombinant MEK1 with an IC50 of 0.28 μM and MEK1/2 in whole cells with an IC50 of 37.4 μM. The inhibition of MEK1/2 was relieved by both Cu+1 and Cu+2 in a concentration-dependent manner. cDDP did not inhibit the upstream pathways responsible for activating MEK1/2, and did not cause an acute depletion of cellular Cu that could account for the reduction in MEK1/2 activity. cDDP was found to bind MEK1/2 in whole cells and the extent of binding was augmented by supplementary Cu and reduced by Cu chelation. Molecular modeling predicts 3 Cu and cDDP binding sites and quantum chemistry calculations indicate that cDDP would be expected to displace Cu from each of these sites. We conclude that, at clinically relevant concentrations, cDDP binds to and inhibits MEK1/2 and that both the binding and inhibitory activity are related to its interaction with Cu bound to MEK1/2. This may provide the basis for useful interactions of cDDP with other drugs that inhibit MAPK pathway signaling.
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Yang L, Skjevik ÅA, Han Du WG, Noodleman L, Walker RC, Götz AW. Data for molecular dynamics simulations of B-type cytochrome c oxidase with the Amber force field. Data Brief 2016; 8:1209-14. [PMID: 27547799 PMCID: PMC4979044 DOI: 10.1016/j.dib.2016.07.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/01/2016] [Accepted: 07/19/2016] [Indexed: 11/25/2022] Open
Abstract
Cytochrome c oxidase (CcO) is a vital enzyme that catalyzes the reduction of molecular oxygen to water and pumps protons across mitochondrial and bacterial membranes. This article presents parameters for the cofactors of ba3-type CcO that are compatible with the all-atom Amber ff12SB and ff14SB force fields. Specifically, parameters were developed for the CuA pair, heme b, and the dinuclear center that consists of heme a3 and CuB bridged by a hydroperoxo group. The data includes geometries in XYZ coordinate format for cluster models that were employed to compute proton transfer energies and derive bond parameters and point charges for the force field using density functional theory. Also included are the final parameter files that can be employed with the Amber leap program to generate input files for molecular dynamics simulations with the Amber software package. Based on the high resolution (1.8 Å) X-ray crystal structure of the ba3-type CcO from Thermus thermophilus (Protein Data Bank ID number PDB: 3S8F), we built a model that is embedded in a POPC lipid bilayer membrane and solvated with TIP3P water molecules and counterions. We provide PDB data files of the initial model and the equilibrated model that can be used for further studies.
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Bajaj P, Götz AW, Paesani F. Toward Chemical Accuracy in the Description of Ion–Water Interactions through Many-Body Representations. I. Halide–Water Dimer Potential Energy Surfaces. J Chem Theory Comput 2016; 12:2698-705. [DOI: 10.1021/acs.jctc.6b00302] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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39
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Han Du WG, Götz AW, Yang L, Walker RC, Noodleman L. A broken-symmetry density functional study of structures, energies, and protonation states along the catalytic O-O bond cleavage pathway in ba3 cytochrome c oxidase from Thermus thermophilus. Phys Chem Chem Phys 2016; 18:21162-71. [PMID: 27094074 DOI: 10.1039/c6cp00349d] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Broken-symmetry density functional calculations have been performed on the [Fea3, CuB] dinuclear center (DNC) of ba3 cytochrome c oxidase from Thermus thermophilus in the states of [Fea3(3+)-(HO2)(-)-CuB(2+), Tyr237(-)] and [Fea3(4+)[double bond, length as m-dash]O(2-), OH(-)-CuB(2+), Tyr237˙], using both PW91-D3 and OLYP-D3 functionals. Tyr237 is a special tyrosine cross-linked to His233, a ligand of CuB. The calculations have shown that the DNC in these states strongly favors the protonation of His376, which is above propionate-A, but not of the carboxylate group of propionate-A. The energies of the structures obtained by constrained geometry optimizations along the O-O bond cleavage pathway between [Fea3(3+)-(O-OH)(-)-CuB(2+), Tyr237(-)] and [Fea3(4+)[double bond, length as m-dash]O(2-)HO(-)-CuB(2+), Tyr237˙] have also been calculated. The transition of [Fea3(3+)-(O-OH)(-)-CuB(2+), Tyr237(-)] → [Fea3(4+)[double bond, length as m-dash]O(2-)HO(-)-CuB(2+), Tyr237˙] shows a very small barrier, which is less than 3.0/2.0 kcal mol(-1) in PW91-D3/OLYP-D3 calculations. The protonation state of His376 does not affect this O-O cleavage barrier. The rate limiting step of the transition from state A (in which O2 binds to Fea3(2+)) to state PM ([Fea3(4+)[double bond, length as m-dash]O(2-), OH(-)-CuB(2+), Tyr237˙], where the O-O bond is cleaved) in the catalytic cycle is, therefore, the proton transfer originating from Tyr237 to O-O to form the hydroperoxo [Fea3(3+)-(O-OH)(-)-CuB(2+), Tyr237(-)] state. The importance of His376 in proton uptake and the function of propionate-A/neutral-Asp372 as a gate to prevent the proton from back-flowing to the DNC are also shown.
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Riera M, Götz AW, Paesani F. The i-TTM model for ab initio-based ion–water interaction potentials. II. Alkali metal ion–water potential energy functions. Phys Chem Chem Phys 2016; 18:30334-30343. [DOI: 10.1039/c6cp02553f] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A new set of i-TTM potential energy functions describing the interactions between alkali metal ions and water molecules is reported.
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Rodríguez JI, Matta CF, Uribe EA, Götz AW, Castillo-Alvarado F, Molina-Brito B. A QTAIM topological analysis of the P3HTPCBM dimer. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2015.11.052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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42
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Medders GR, Götz AW, Morales MA, Bajaj P, Paesani F. On the representation of many-body interactions in water. J Chem Phys 2015; 143:104102. [DOI: 10.1063/1.4930194] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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43
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Yao SA, Martin-Diaconescu V, Infante I, Lancaster KM, Götz AW, DeBeer S, Berry JF. Electronic Structure of Ni2E2 Complexes (E = S, Se, Te) and a Global Analysis of M2E2 Compounds: A Case for Quantized E2n– Oxidation Levels with n = 2, 3, or 4. J Am Chem Soc 2015; 137:4993-5011. [DOI: 10.1021/ja511607j] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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44
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Mones L, Jones A, Götz AW, Laino T, Walker RC, Leimkuhler B, Csányi G, Bernstein N. The adaptive buffered force QM/MM method in the CP2K and AMBER software packages. J Comput Chem 2015; 36:633-48. [PMID: 25649827 PMCID: PMC4351341 DOI: 10.1002/jcc.23839] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 12/03/2014] [Accepted: 12/22/2014] [Indexed: 11/17/2022]
Abstract
The implementation and validation of the adaptive buffered force (AdBF) quantum-mechanics/molecular-mechanics (QM/MM) method in two popular packages, CP2K and AMBER are presented. The implementations build on the existing QM/MM functionality in each code, extending it to allow for redefinition of the QM and MM regions during the simulation and reducing QM-MM interface errors by discarding forces near the boundary according to the buffered force-mixing approach. New adaptive thermostats, needed by force-mixing methods, are also implemented. Different variants of the method are benchmarked by simulating the structure of bulk water, water autoprotolysis in the presence of zinc and dimethyl-phosphate hydrolysis using various semiempirical Hamiltonians and density functional theory as the QM model. It is shown that with suitable parameters, based on force convergence tests, the AdBF QM/MM scheme can provide an accurate approximation of the structure in the dynamical QM region matching the corresponding fully QM simulations, as well as reproducing the correct energetics in all cases. Adaptive unbuffered force-mixing and adaptive conventional QM/MM methods also provide reasonable results for some systems, but are more likely to suffer from instabilities and inaccuracies. © 2015 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.
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Noodleman L, Han Du WG, Fee J, Götz AW, Walker RC. Linking chemical electron-proton transfer to proton pumping in cytochrome c oxidase: broken-symmetry DFT exploration of intermediates along the catalytic reaction pathway of the iron-copper dinuclear complex. Inorg Chem 2014; 53:6458-72. [PMID: 24960612 PMCID: PMC4095914 DOI: 10.1021/ic500363h] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Indexed: 12/23/2022]
Abstract
After a summary of the problem of coupling electron and proton transfer to proton pumping in cytochrome c oxidase, we present the results of our earlier and recent density functional theory calculations for the dinuclear Fe-a3-CuB reaction center in this enzyme. A specific catalytic reaction wheel diagram is constructed from the calculations, based on the structures and relative energies of the intermediate states of the reaction cycle. A larger family of tautomers/protonation states is generated compared to our earlier work, and a new lowest-energy pathway is proposed. The entire reaction cycle is calculated for the new smaller model (about 185-190 atoms), and two selected arcs of the wheel are chosen for calculations using a larger model (about 205 atoms). We compare the structural and redox energetics and protonation calculations with available experimental data. The reaction cycle map that we have built is positioned for further improvement and testing against experiment.
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Götz AW, Autschbach J, Visscher L. Calculation of nuclear spin-spin coupling constants using frozen density embedding. J Chem Phys 2014; 140:104107. [DOI: 10.1063/1.4864053] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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47
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Götz AW, Bucher D, Lindert S, McCammon JA. Dipeptide Aggregation in Aqueous Solution from Fixed Point-Charge Force Fields. J Chem Theory Comput 2014; 10:1631-1637. [PMID: 24803868 PMCID: PMC3986234 DOI: 10.1021/ct401049q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Indexed: 11/29/2022]
Abstract
The description of aggregation processes with molecular dynamics simulations is a playground for testing biomolecular force fields, including a new generation of force fields that explicitly describe electronic polarization. In this work, we study a system consisting of 50 glycyl-l-alanine (Gly-Ala) dipeptides in solution with 1001 water molecules. Neutron diffraction experiments have shown that at this concentration, Gly-Ala aggregates into large clusters. However, general-purpose force fields in combination with established water models can fail to correctly describe this aggregation process, highlighting important deficiencies in how solute-solute and solute-solvent interactions are parametrized in these force fields. We found that even for the fully polarizable AMOEBA force field, the degree of association is considerably underestimated. Instead, a fixed point-charge approach based on the newly developed IPolQ scheme [Cerutti et al. J. Phys. Chem.2013, 117, 2328] allows for the correct modeling of the dipeptide aggregation in aqueous solution. This result should stimulate interest in novel fitting schemes that aim to improve the description of the solvent polarization effect within both explicitly polarizable and fixed point-charge frameworks.
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Götz AW, Clark MA, Walker RC. An extensible interface for QM/MM molecular dynamics simulations with AMBER. J Comput Chem 2014; 35:95-108. [PMID: 24122798 PMCID: PMC4063945 DOI: 10.1002/jcc.23444] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 08/05/2013] [Accepted: 08/31/2013] [Indexed: 11/09/2022]
Abstract
We present an extensible interface between the AMBER molecular dynamics (MD) software package and electronic structure software packages for quantum mechanical (QM) and mixed QM and classical molecular mechanical (MM) MD simulations within both mechanical and electronic embedding schemes. With this interface, ab initio wave function theory and density functional theory methods, as available in the supported electronic structure software packages, become available for QM/MM MD simulations with AMBER. The interface has been written in a modular fashion that allows straight forward extensions to support additional QM software packages and can easily be ported to other MD software. Data exchange between the MD and QM software is implemented by means of files and system calls or the message passing interface standard. Based on extensive tests, default settings for the supported QM packages are provided such that energy is conserved for typical QM/MM MD simulations in the microcanonical ensemble. Results for the free energy of binding of calcium ions to aspartate in aqueous solution comparing semiempirical and density functional Hamiltonians are shown to demonstrate features of this interface.
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Knott BC, Haddad Momeni M, Crowley MF, Mackenzie LF, Götz AW, Sandgren M, Withers SG, Ståhlberg J, Beckham GT. The Mechanism of Cellulose Hydrolysis by a Two-Step, Retaining Cellobiohydrolase Elucidated by Structural and Transition Path Sampling Studies. J Am Chem Soc 2013; 136:321-9. [DOI: 10.1021/ja410291u] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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50
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Salomon-Ferrer R, Götz AW, Poole D, Le Grand S, Walker RC. Routine Microsecond Molecular Dynamics Simulations with AMBER on GPUs. 2. Explicit Solvent Particle Mesh Ewald. J Chem Theory Comput 2013; 9:3878-88. [PMID: 26592383 DOI: 10.1021/ct400314y] [Citation(s) in RCA: 2198] [Impact Index Per Article: 199.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We present an implementation of explicit solvent all atom classical molecular dynamics (MD) within the AMBER program package that runs entirely on CUDA-enabled GPUs. First released publicly in April 2010 as part of version 11 of the AMBER MD package and further improved and optimized over the last two years, this implementation supports the three most widely used statistical mechanical ensembles (NVE, NVT, and NPT), uses particle mesh Ewald (PME) for the long-range electrostatics, and runs entirely on CUDA-enabled NVIDIA graphics processing units (GPUs), providing results that are statistically indistinguishable from the traditional CPU version of the software and with performance that exceeds that achievable by the CPU version of AMBER software running on all conventional CPU-based clusters and supercomputers. We briefly discuss three different precision models developed specifically for this work (SPDP, SPFP, and DPDP) and highlight the technical details of the approach as it extends beyond previously reported work [Götz et al., J. Chem. Theory Comput. 2012, DOI: 10.1021/ct200909j; Le Grand et al., Comp. Phys. Comm. 2013, DOI: 10.1016/j.cpc.2012.09.022].We highlight the substantial improvements in performance that are seen over traditional CPU-only machines and provide validation of our implementation and precision models. We also provide evidence supporting our decision to deprecate the previously described fully single precision (SPSP) model from the latest release of the AMBER software package.
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