QM/MM-Based Fitting of Atomic Polarizabilities for Use in Condensed-Phase Biomolecular Simulation

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• 作者：C. Ruben Vosmeer ; Ari毛n S. Rustenburg ; Julia E. Rice ; Hans W. Horn ; William C. Swope ; Daan P. Geerke
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2012
• 出版时间：October 9, 2012
• 年：2012
• 卷：8
• 期：10
• 页码：3839-3853
• 全文大小：802K
• 年卷期：v.8,no.10(October 9, 2012)
• ISSN：1549-9626

文摘

Accounting for electronic polarization effects in biomolecular simulation (by using a polarizable force field) can increase the accuracy of simulation results. However, the use of gas-phase estimates of atomic polarizabilities 伪_i usually leads to overpolarization in condensed-phase systems. In the current work, a combined QM/MM approach has been employed to obtain condensed-phase estimates of atomic polarizabilities for water and methanol (QM) solutes in the presence of (MM) solvents of different polarity. In a next step, the validity of the linear response and isotropy assumptions were evaluated based on the observed condensed-phase distributions of 伪_i values. The observed anisotropy and low average values for the polarizability of methanol鈥檚 carbon atom in polar solvents was explained in terms of strong solute鈥搒olvent interactions involving its adjacent hydroxyl group. Our QM/MM estimates for atomic polarizabilities were found to be close to values used in previously reported polarizable water and methanol models. Using our estimate for 伪_O of methanol, a single set of polarizable force field parameters was obtained that is directly transferable between environments of different polarity.