Kirkwood-Buff analysis of aqueous N-methylacetamide and acetamide solutions modeled by the CHARMM additive and Drude polarizable force fields.

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TitleKirkwood-Buff analysis of aqueous N-methylacetamide and acetamide solutions modeled by the CHARMM additive and Drude polarizable force fields.
Publication TypeJournal Article
Year of Publication2013
AuthorsLin, B, Lopes, PEM, Roux, B, Mackerell, AD
JournalJ Chem Phys
Volume139
Issue8
Pagination084509
Date Published2013 Aug 28
ISSN1089-7690
KeywordsAcetamides, Models, Molecular, Molecular Conformation, Molecular Dynamics Simulation, Solutions, Thermodynamics, Water
Abstract

Kirkwood-Buff analysis was performed on aqueous solutions of N-methylacetamide and acetamide using the Chemistry at HARvard Molecular Mechanics additive and Drude polarizable all-atom force fields. Comparison of a range of properties with experimental results, including Kirkwood-Buff integrals, excess coordination numbers, solution densities, partial molar values, molar enthalpy of mixing, showed both models to be well behaved at higher solute concentrations with the Drude model showing systematic improvement at lower solution concentrations. However, both models showed difficulties reproducing experimental activity derivatives and the excess Gibbs energy, with the Drude model performing slightly better. At the molecular level, the improved agreement of the Drude model at low solute concentrations is due to increased structure in the solute-solute and solute-solvent interactions. The present results indicate that the explicit inclusion of electronic polarization leads to improved modeling of dilute solutions even when those properties are not included as target data during force field optimization.

DOI10.1063/1.4818731
Alternate JournalJ Chem Phys
PubMed ID24007020
PubMed Central IDPMC3772949
Grant ListR01 GM072558 / GM / NIGMS NIH HHS / United States
GM051501 / GM / NIGMS NIH HHS / United States
R01 GM051501 / GM / NIGMS NIH HHS / United States
R29 GM051501 / GM / NIGMS NIH HHS / United States
GM072558 / GM / NIGMS NIH HHS / United States