1
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Kříž K, Schmidt L, Andersson AT, Walz MM, van der Spoel D. An Imbalance in the Force: The Need for Standardized Benchmarks for Molecular Simulation. J Chem Inf Model 2023; 63:412-431. [PMID: 36630710 PMCID: PMC9875315 DOI: 10.1021/acs.jcim.2c01127] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Indexed: 01/12/2023]
Abstract
Force fields (FFs) for molecular simulation have been under development for more than half a century. As with any predictive model, rigorous testing and comparisons of models critically depends on the availability of standardized data sets and benchmarks. While such benchmarks are rather common in the fields of quantum chemistry, this is not the case for empirical FFs. That is, few benchmarks are reused to evaluate FFs, and development teams rather use their own training and test sets. Here we present an overview of currently available tests and benchmarks for computational chemistry, focusing on organic compounds, including halogens and common ions, as FFs for these are the most common ones. We argue that many of the benchmark data sets from quantum chemistry can in fact be reused for evaluating FFs, but new gas phase data is still needed for compounds containing phosphorus and sulfur in different valence states. In addition, more nonequilibrium interaction energies and forces, as well as molecular properties such as electrostatic potentials around compounds, would be beneficial. For the condensed phases there is a large body of experimental data available, and tools to utilize these data in an automated fashion are under development. If FF developers, as well as researchers in artificial intelligence, would adopt a number of these data sets, it would become easier to compare the relative strengths and weaknesses of different models and to, eventually, restore the balance in the force.
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Affiliation(s)
- Kristian Kříž
- Department
of Cell and Molecular Biology, Uppsala University, Box 596, SE-75124Uppsala, Sweden
| | - Lisa Schmidt
- Faculty
of Biosciences, University of Heidelberg, Heidelberg69117, Germany
| | - Alfred T. Andersson
- Department
of Cell and Molecular Biology, Uppsala University, Box 596, SE-75124Uppsala, Sweden
| | - Marie-Madeleine Walz
- Department
of Cell and Molecular Biology, Uppsala University, Box 596, SE-75124Uppsala, Sweden
| | - David van der Spoel
- Department
of Cell and Molecular Biology, Uppsala University, Box 596, SE-75124Uppsala, Sweden
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2
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Fadda E. Molecular simulations of complex carbohydrates and glycoconjugates. Curr Opin Chem Biol 2022; 69:102175. [PMID: 35728307 DOI: 10.1016/j.cbpa.2022.102175] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 11/17/2022]
Abstract
Complex carbohydrates (glycans) are the most abundant and versatile biopolymers in nature. The broad diversity of biochemical functions that carbohydrates cover is a direct consequence of the variety of 3D architectures they can adopt, displaying branched or linear arrangements, widely ranging in sizes, and with the highest diversity of building blocks of any other natural biopolymer. Despite this unparalleled complexity, a common denominator can be found in the glycans' inherent flexibility, which hinders experimental characterization, but that can be addressed by high-performance computing (HPC)-based molecular simulations. In this short review, I present and discuss the state-of-the-art of molecular simulations of complex carbohydrates and glycoconjugates, highlighting methodological strengths and weaknesses, important insights through emblematic case studies, and suggesting perspectives for future developments.
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Affiliation(s)
- Elisa Fadda
- Department of Chemistry and Hamilton Institute, Maynooth University, Ireland.
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3
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Franco LR, Toledo KCF, Matias TA, Benavides PA, Cezar HM, Araujo CM, Coutinho K, Araki K. Unraveling the acid-base characterization and solvent effects on the structural and electronic properties of a bis-bidentate bridging ligand. Phys Chem Chem Phys 2022; 24:10222-10240. [PMID: 35420602 DOI: 10.1039/d1cp03912a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Understanding the interactions and the solvent effects on the distribution of several species in equilibrium and how it can influence the 1H-NMR properties, spectroscopy (UV-vis absorption), and the acid-base equilibria can be especially challenging. This is the case of a bis-bidentate bridging ligand bis(2-pyridyl)-benzo-bis(imidazole), where the two pyridyl and four imidazolyl nitrogen atoms can be protonated in different ways, depending on the solvent, generating many isomeric/tautomeric species. Herein, we report a combined theoretical-experimental approach based on a sequential quantum mechanics/molecular mechanics procedure that was successfully applied to describe in detail the acid-base characterization and its effects on the electronic properties of such a molecule in solution. The calculated free-energies allowed the identification of the main species present in solution as a function of the solvent polarity, and its effects on the magnetic shielding of protons (1H-NMR chemical shifts), the UV-vis absorption spectra, and the acid-base equilibrium constants (pKas) in aqueous solution. Three acid-base equilibrium constants were experimentally/theoretically determined (pKa1 = 1.3/1.2, pKa2 = 2.1/2.2 and pKa5 = 10.1/11.3) involving mono-deprotonated and mono-protonated cis and trans species. Interestingly, other processes with pKa3 = 3.7 and pKa4 = 6.0 were also experimentally determined and assigned to the protonation and deprotonation of dimeric species. The dimerization of the most stable neutral species was investigated by Monte Carlo simulations and its electronic effects were considered for the elucidation of the UV-vis absorption bands, revealing transitions mainly with the charge-transfer characteristic and involving both the monomeric species and the dimeric species. The good matching of the theoretical and experimental results provides an atomistic insight into the solvent effects on the electronic properties of this bis-bidentate bridging ligand.
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Affiliation(s)
- Leandro Rezende Franco
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, 05508-090 São Paulo, SP, Brazil. .,Department of Engineering and Physics, Karlstad University, 65188 Karlstad, Sweden
| | | | - Tiago Araujo Matias
- Instituto de Química, Universidade de São Paulo, Av. Lineu Prestes 748, Butantã, 05508-000 São Paulo, SP, Brazil.
| | - Paola Andrea Benavides
- Instituto de Química, Universidade de São Paulo, Av. Lineu Prestes 748, Butantã, 05508-000 São Paulo, SP, Brazil.
| | - Henrique Musseli Cezar
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, 05508-090 São Paulo, SP, Brazil.
| | - C Moyses Araujo
- Department of Engineering and Physics, Karlstad University, 65188 Karlstad, Sweden.,Materials Theory Division, Department of Physics and Astronomy, Ångström Laboratory, Uppsala University, 75120 Uppsala, Sweden
| | - Kaline Coutinho
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, 05508-090 São Paulo, SP, Brazil.
| | - Koiti Araki
- Instituto de Química, Universidade de São Paulo, Av. Lineu Prestes 748, Butantã, 05508-000 São Paulo, SP, Brazil.
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4
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Qiu Y, Shan W, Zhang H. Force Field Benchmark of Amino Acids. 3. Hydration with Scaled Lennard-Jones Interactions. J Chem Inf Model 2021; 61:3571-3582. [PMID: 34185520 DOI: 10.1021/acs.jcim.1c00339] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Classical protein force fields were reported with too weak protein-water interactions relative to protein-protein interactions, leading to more compact structures and artificial protein aggregation. Here we investigated the impacts of scaled Lennard-Jones (LJ) interactions on the hydration of amino acids and the simulation of folded and intrinsically disordered proteins (IDPs). The obtained optimal scaling parameters reproduce accurately hydration free energies of neutral amino acid side chain analogues and do not affect the compactness and structural stability of folded proteins significantly. The scaling leads to less compact IDPs and varies from case to case. Strengthening the interactions between protein and water oxygen or hydrogen atoms by increasing the interacting LJ well depth (ε) appears more effective than weakening protein-protein interactions by reducing the interacting dispersion coefficients (C6). We demonstrate that weakening water-water interactions is a solution as well to obtaining more favorable protein-water interactions in an indirect way, although modern force fields like Amber ff19SB and a99SB-disp tend to use water models with strong water-water interactions. This is likely a compromise between strong protein-protein interactions and strong water-water interactions. Independent optimization of protein force fields and water models is therefore needed to make both interactions more close to reality, leading to good accuracy without bias or scaling.
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Affiliation(s)
- Yejie Qiu
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083 Beijing, China
| | - Wenjie Shan
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083 Beijing, China
| | - Haiyang Zhang
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083 Beijing, China
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5
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Spoel D, Zhang J, Zhang H. Quantitative predictions from molecular simulations using explicit or implicit interactions. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2021. [DOI: 10.1002/wcms.1560] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- David Spoel
- Uppsala Center for Computational Chemistry, Science for Life Laboratory, Department of Cell and Molecular Biology Uppsala University Uppsala Sweden
| | - Jin Zhang
- Department of Chemistry Southern University of Science and Technology Shenzhen China
| | - Haiyang Zhang
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering University of Science and Technology Beijing Beijing China
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6
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Kashefolgheta S, Wang S, Acree WE, Hünenberger PH. Evaluation of nine condensed-phase force fields of the GROMOS, CHARMM, OPLS, AMBER, and OpenFF families against experimental cross-solvation free energies. Phys Chem Chem Phys 2021; 23:13055-13074. [PMID: 34105547 PMCID: PMC8207520 DOI: 10.1039/d1cp00215e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/28/2021] [Indexed: 12/02/2022]
Abstract
Experimental solvation free energies are nowadays commonly included as target properties in the validation of condensed-phase force fields, sometimes even in their calibration. In a previous article [Kashefolgheta et al., J. Chem. Theory. Comput., 2020, 16, 7556-7580], we showed how the involved comparison between experimental and simulation results could be made more systematic by considering a full matrix of cross-solvation free energies . For a set of N molecules that are all in the liquid state under ambient conditions, such a matrix encompasses N×N entries for considering each of the N molecules either as solute (A) or as solvent (B). In the quoted study, a cross-solvation matrix of 25 × 25 experimental value was introduced, considering 25 small molecules representative for alkanes, chloroalkanes, ethers, ketones, esters, alcohols, amines, and amides. This experimental data was used to compare the relative accuracies of four popular condensed-phase force fields, namely GROMOS-2016H66, OPLS-AA, AMBER-GAFF, and CHARMM-CGenFF. In the present work, the comparison is extended to five additional force fields, namely GROMOS-54A7, GROMOS-ATB, OPLS-LBCC, AMBER-GAFF2, and OpenFF. Considering these nine force fields, the correlation coefficients between experimental values and simulation results range from 0.76 to 0.88, the root-mean-square errors (RMSEs) from 2.9 to 4.8 kJ mol-1, and average errors (AVEEs) from -1.5 to +1.0 kJ mol-1. In terms of RMSEs, GROMOS-2016H66 and OPLS-AA present the best accuracy (2.9 kJ mol-1), followed by OPLS-LBCC, AMBER-GAFF2, AMBER-GAFF, and OpenFF (3.3 to 3.6 kJ mol-1), and then by GROMOS-54A7, CHARM-CGenFF, and GROMOS-ATB (4.0 to 4.8 kJ mol-1). These differences are statistically significant but not very pronounced, and are distributed rather heterogeneously over the set of compounds within the different force fields.
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Affiliation(s)
- Sadra Kashefolgheta
- Laboratorium für Physikalische Chemie, ETH Zürich, ETH-Hönggerberg, HCICH-8093 ZürichSwitzerland+41 44 632 55 03
| | - Shuzhe Wang
- Laboratorium für Physikalische Chemie, ETH Zürich, ETH-Hönggerberg, HCICH-8093 ZürichSwitzerland+41 44 632 55 03
| | - William E. Acree
- Department of Chemistry, University of North Texas1155 Union Circle Drive #305070DentonTexas 76203USA
| | - Philippe H. Hünenberger
- Laboratorium für Physikalische Chemie, ETH Zürich, ETH-Hönggerberg, HCICH-8093 ZürichSwitzerland+41 44 632 55 03
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7
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Jedwabny W, Dyguda-Kazimierowicz E, Pernal K, Szalewicz K, Patkowski K. Extension of an Atom-Atom Dispersion Function to Halogen Bonds and Its Use for Rational Design of Drugs and Biocatalysts. J Phys Chem A 2021; 125:1787-1799. [PMID: 33620223 PMCID: PMC8028329 DOI: 10.1021/acs.jpca.0c11347] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/10/2021] [Indexed: 12/17/2022]
Abstract
A dispersion function Das in the form of a damped atom-atom asymptotic expansion fitted to ab initio dispersion energies from symmetry-adapted perturbation theory was improved and extended to systems containing heavier halogen atoms. To illustrate its performance, the revised Das function was implemented in the multipole first-order electrostatic and second-order dispersion (MED) scoring model. The extension has allowed applications to a much larger set of biocomplexes than it was possible with the original Das. A reasonable correlation between MED and experimentally determined inhibitory activities was achieved in a number of test cases, including structures featuring nonphysically shortened intermonomer distances, which constitute a particular challenge for binding strength predictions. Since the MED model is also computationally efficient, it can be used for reliable and rapid assessment of the ligand affinity or multidimensional scanning of amino acid side-chain conformations in the process of rational design of novel drugs or biocatalysts.
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Affiliation(s)
- Wiktoria Jedwabny
- Department
of Chemistry, Wrocław University of
Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Edyta Dyguda-Kazimierowicz
- Department
of Chemistry, Wrocław University of
Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Katarzyna Pernal
- Institute
of Physics, Łódź University
of Technology, Wólczańska
219, 90-924 Łódź, Poland
| | - Krzysztof Szalewicz
- Department
of Physics and Astronomy, University of
Delaware, Newark, Delaware 19716, United
States
| | - Konrad Patkowski
- Department
of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, United States
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8
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Kashefolgheta S, Oliveira MP, Rieder SR, Horta BAC, Acree WE, Hünenberger PH. Evaluating Classical Force Fields against Experimental Cross-Solvation Free Energies. J Chem Theory Comput 2020; 16:7556-7580. [DOI: 10.1021/acs.jctc.0c00688] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Sadra Kashefolgheta
- Laboratorium für Physikalische Chemie, ETH Zürich, ETH-Hönggerberg, HCI, CH-8093 Zürich, Switzerland
| | - Marina P. Oliveira
- Laboratorium für Physikalische Chemie, ETH Zürich, ETH-Hönggerberg, HCI, CH-8093 Zürich, Switzerland
| | - Salomé R. Rieder
- Laboratorium für Physikalische Chemie, ETH Zürich, ETH-Hönggerberg, HCI, CH-8093 Zürich, Switzerland
| | - Bruno A. C. Horta
- Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-909, Brazil
| | - William E. Acree
- Department of Chemistry, University of North Texas, 1155 Union Circle Drive #305070, Denton, Texas 76203, United States
| | - Philippe H. Hünenberger
- Laboratorium für Physikalische Chemie, ETH Zürich, ETH-Hönggerberg, HCI, CH-8093 Zürich, Switzerland
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9
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Mohebifar M, Rowley CN. An efficient and accurate model for water with an improved non-bonded potential. J Chem Phys 2020; 153:134105. [PMID: 33032419 DOI: 10.1063/5.0014469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A molecular mechanical model for liquid water is developed that uses a physically motivated potential to represent Pauli repulsion and dispersion instead of the standard Lennard-Jones potential. The model has three atomic sites and a virtual site located on the ∠HOH bisector (i.e., a TIP4P-type model). Pauli-repulsive interactions are represented using a Buckingham-type exponential decay potential. Dispersion interactions are represented by both C6/r6 and C8/r8 terms. This higher order C8 dispersion term has been neglected by most force fields. The ForceBalance code was used to define parameters that optimally reproduce the experimental physical properties of liquid water. The resulting model is in good agreement with the experimental density, dielectric constant, enthalpy of vaporization, isothermal compressibility, thermal expansion coefficient, diffusion coefficient, and radial distribution function. A graphical processing unit-accelerated implementation of this improved non-bonded potential can be employed in OpenMM without modification by using the CustomNonBondedForce feature. The efficient and automated parameterization of these non-bonded potentials provides a rational strategy to define a new molecular mechanical force field that treats repulsion and dispersion interactions more rigorously without major modifications to the existing simulation codes or a substantially larger computational cost.
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Affiliation(s)
- Mohamad Mohebifar
- Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X7, Canada
| | - Christopher N Rowley
- Department of Chemistry, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X7, Canada
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10
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Kamiya N, Kayanuma M, Fujitani H, Shinoda K. A New Lipid Force Field (FUJI). J Chem Theory Comput 2020; 16:3664-3676. [PMID: 32384238 DOI: 10.1021/acs.jctc.9b01195] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
To explore inhomogeneous and anisotropic systems such as lipid bilayers, the Lennard-Jones particle mesh Ewald (LJ-PME) method has been applied without a conventional isotropic dispersion correction. As the popular AMBER and CHARMM lipid force fields were developed using a cutoff scheme, their lipid bilayers unacceptably shrink when using the LJ-PME method. In this study, a new all-atom lipid force field (FUJI) was developed on the basis of the AMBER force-field scheme including the Lipid14 van der Waals parameters. Point charges were calculated using the restrained electrostatic potentials of many lipid conformers. Further, torsion energy profiles were calculated using high-level ab initio molecular orbitals (LCCSD(T)/Aug-cc-pVTZ//LMP2/Aug-cc-pVTZ), following which the molecular mechanical dihedral parameters were derived through a fast Fourier transform. By incorporation of these parameters into a new lipid force field without fitting experimental data, the desired lipid characteristics such as the area per lipid and lateral diffusion coefficients were obtained through GROMACS molecular dynamics simulations using the LJ-PME method and virtual hydrogen sites. The calculated area per lipid and lateral diffusion coefficients showed satisfactory agreement with experimental data. Furthermore, the electron-density profiles along the membrane normal were calculated for pure lipid bilayers, and the resulting membrane thicknesses agreed well with the experimental values. As the new lipid force field is compatible with FUJI for protein and small molecules, the new FUJI force field will offer accurate modeling for complex systems consisting of various membrane proteins and lipids.
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Affiliation(s)
- Nozomu Kamiya
- Fujitsu Limited Bio-IT R&D Office, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Megumi Kayanuma
- Research Center for Computational Design of Advanced Functional Materials, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Hideaki Fujitani
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Keiko Shinoda
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
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11
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Kubincová A, Riniker S, Hünenberger PH. Reaction-field electrostatics in molecular dynamics simulations: development of a conservative scheme compatible with an atomic cutoff. Phys Chem Chem Phys 2020; 22:26419-26437. [DOI: 10.1039/d0cp03835k] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Shifting and switching schemes are developed to enable strict energy conservation in molecular dynamics simulations relying on reaction-field electrostatic (as well as Lennard-Jones) interactions with an atom-based cutoff truncation.
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Affiliation(s)
| | - Sereina Riniker
- Laboratory of Physical Chemistry
- ETH Zurich
- 8093 Zurich
- Switzerland
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12
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Bashardanesh Z, Elf J, Zhang H, van der Spoel D. Rotational and Translational Diffusion of Proteins as a Function of Concentration. ACS OMEGA 2019; 4:20654-20664. [PMID: 31858051 PMCID: PMC6906769 DOI: 10.1021/acsomega.9b02835] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 11/14/2019] [Indexed: 05/21/2023]
Abstract
Atomistic simulations of three different proteins at different concentrations are performed to obtain insight into protein mobility as a function of protein concentration. We report on simulations of proteins from diluted to the physiological water concentration (about 70% of the mass). First, the viscosity was computed and found to increase by a factor of 7-9 going from pure water to the highest protein concentration, in excellent agreement with in vivo nuclear magnetic resonance results. At a physiological concentration of proteins, the translational diffusion is found to be slowed down to about 30% of the in vitro values. The slow-down of diffusion found here using atomistic models is slightly more than that of a hard sphere model that neglects the electrostatic interactions. Interestingly, rotational diffusion of proteins is slowed down somewhat more (by about 80-95% compared to in vitro values) than translational diffusion, in line with experimental findings and consistent with the increased viscosity. The finding that rotation is retarded more than translation is attributed to solvent-separated clustering. No direct interactions between the proteins are found, and the clustering can likely be attributed to dispersion interactions that are stronger between proteins than between protein and water. Based on these simulations, we can also conclude that the internal dynamics of the proteins in our study are affected only marginally under crowding conditions, and the proteins become somewhat more stable at higher concentrations. Simulations were performed using a force field that was tuned for dealing with crowding conditions by strengthening the protein-water interactions. This force field seems to lead to a reproducible partial unfolding of an α-helix in one of the proteins, an effect that was not observed in the unmodified force field.
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Affiliation(s)
- Zahedeh Bashardanesh
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-75124 Uppsala, Sweden
| | - Johan Elf
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-75124 Uppsala, Sweden
| | - Haiyang Zhang
- Department
of Biological Science and Engineering, School of Chemistry and Biological
Engineering, University of Science and Technology
Beijing, 100083 Beijing, China
| | - David van der Spoel
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-75124 Uppsala, Sweden
- E-mail: . Phone: +46 18 4714205
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13
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Oliveira Bortot L, Bashardanesh Z, van der Spoel D. Making Soup: Preparing and Validating Models of the Bacterial Cytoplasm for Molecular Simulation. J Chem Inf Model 2019; 60:322-331. [DOI: 10.1021/acs.jcim.9b00971] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Leandro Oliveira Bortot
- Laboratory of Biological Physics, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n, 14040-903 Ribeirão Preto-SP, Brazil
| | - Zahedeh Bashardanesh
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Box 596, SE-75124 Uppsala, Sweden
| | - David van der Spoel
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Box 596, SE-75124 Uppsala, Sweden
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14
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van der Spoel D, Manzetti S, Zhang H, Klamt A. Prediction of Partition Coefficients of Environmental Toxins Using Computational Chemistry Methods. ACS OMEGA 2019; 4:13772-13781. [PMID: 31497695 PMCID: PMC6713992 DOI: 10.1021/acsomega.9b01277] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 06/27/2019] [Indexed: 05/05/2023]
Abstract
The partitioning of compounds between aqueous and other phases is important for predicting toxicity. Although thousands of octanol-water partition coefficients have been measured, these represent only a small fraction of the anthropogenic compounds present in the environment. The octanol phase is often taken to be a mimic of the inner parts of phospholipid membranes. However, the core of such membranes is typically more hydrophobic than octanol, and other partition coefficients with other compounds may give complementary information. Although a number of (cheap) empirical methods exist to compute octanol-water (log k OW) and hexadecane-water (log k HW) partition coefficients, it would be interesting to know whether physics-based models can predict these crucial values more accurately. Here, we have computed log k OW and log k HW for 133 compounds from seven different pollutant categories as well as a control group using the solvation model based on electronic density (SMD) protocol based on Hartree-Fock (HF) or density functional theory (DFT) and the COSMO-RS method. For comparison, XlogP3 (log k OW) values were retrieved from the PubChem database, and KowWin log k OW values were determined as well. For 24 of these compounds, log k OW was computed using potential of mean force (PMF) calculations based on classical molecular dynamics simulations. A comparison of the accuracy of the methods shows that COSMO-RS, KowWin, and XlogP3 all have a root-mean-square deviation (rmsd) from the experimental data of ≈0.4 log units, whereas the SMD protocol has an rmsd of 1.0 log units using HF and 0.9 using DFT. PMF calculations yield the poorest accuracy (rmsd = 1.1 log units). Thirty-six out of 133 calculations are for compounds without known log k OW, and for these, we provide what we consider a robust prediction, in the sense that there are few outliers, by averaging over the methods. The results supplied may be instrumental when developing new methods in computational ecotoxicity. The log k HW values are found to be strongly correlated to log k OW for most compounds.
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Affiliation(s)
- David van der Spoel
- Uppsala Center for
Computational Chemistry, Science for Life Laboratory, Department of
Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-75124 Uppsala, Sweden
- E-mail: . Phone: +46 18 4714205
| | - Sergio Manzetti
- Uppsala Center for
Computational Chemistry, Science for Life Laboratory, Department of
Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-75124 Uppsala, Sweden
- Fjordforsk A.S., Institute
for Science and Technology, Midtun, 6894 Vangsnes, Norway
| | - Haiyang Zhang
- Department of Biological Science and Engineering,
School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 100083 Beijing, China
| | - Andreas Klamt
- COSMOlogic GmbH & Co. KG, Imbacher Weg 46, D-51379 Leverkusen, Germany
- Institute of Physical and Theoretical Chemistry, University of Regensburg, 93053 Regensburg, Germany
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Krämer A, Pickard FC, Huang J, Venable RM, Simmonett AC, Reith D, Kirschner KN, Pastor RW, Brooks BR. Interactions of Water and Alkanes: Modifying Additive Force Fields to Account for Polarization Effects. J Chem Theory Comput 2019; 15:3854-3867. [PMID: 31002505 DOI: 10.1021/acs.jctc.9b00016] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Atomistic biomolecular simulations predominantly utilize additive force fields (FF), where the electrostatic potential is modeled by fixed point charges. Among other consequences, the lack of polarizability in these models undermines the balance of hydrophilic/hydrophobic nonbonded interactions. Simulations of water/alkane systems using the TIP3P water model and CHARMM36 parameters reveal a 1 kcal/mol overestimate of the experimental transfer free energy of water to hexadecane; more recent optimized water models (SPC/E, TIP4P/2005, TIP4P-Ew, TIP3P-FB, TIP4P-FB, OPC, TIP4P-D) overestimate this transfer free energy by approximately 2 kcal/mol. In contrast, the polarizable SWM4-NDP and SWM6 water models reproduce experimental values to within statistical error. As an alternative to explicitly modeling polarizability, this paper develops an efficient automated workflow to optimize pair-specific Lennard-Jones parameters within an additive FF. Water/hexadecane is used as a prototype and the free energy of water transfer to hexadecane as a target. The optimized model yields quantitative agreement with the experimental transfer free energy and improves the water/hexadecane interfacial tension by 6%. Simulations of five different lipid bilayers show a strong increase of water permeabilities compared to the unmodified CHARMM36 lipid FF which consistently improves match with experiment: the order-of-magnitude underestimate for monounsaturated bilayers is rectified and the factor of 2.8-4 underestimate for saturated bilayers is turned into a factor of 1.5-3 overestimate. While agreement with experiment is decreased for the diffusion constant of water in hexadecane, alkane transfer free energies, and the bilayers' area per lipid, the method provides a permeant-specific route to achieve a wide range of heterogeneous observables via rapidly optimized pairwise parameters.
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Affiliation(s)
- Andreas Krämer
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States.,Institute of Technology, Resource and Energy-Efficient Engineering , Bonn-Rhein-Sieg University of Applied Sciences , Grantham-Allee 20 , 53757 Sankt Augustin , Germany
| | - Frank C Pickard
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Jing Huang
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States.,School of Life Sciences , Westlake University , 18 Shilongshan Road , Hangzhou 310024 , Zhejiang China.,Department of Pharmaceutical Science, School of Pharmacy , University of Maryland , 20 Penn Street , Baltimore , Maryland 21201 , United States
| | - Richard M Venable
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Andrew C Simmonett
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Dirk Reith
- Institute of Technology, Resource and Energy-Efficient Engineering , Bonn-Rhein-Sieg University of Applied Sciences , Grantham-Allee 20 , 53757 Sankt Augustin , Germany
| | - Karl N Kirschner
- Institute of Technology, Resource and Energy-Efficient Engineering , Bonn-Rhein-Sieg University of Applied Sciences , Grantham-Allee 20 , 53757 Sankt Augustin , Germany
| | - Richard W Pastor
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Bernard R Brooks
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States
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