Electronic polarizability is an important factor in molecular interactions. In the commonly used molecular mechanics force fields, however, there is an inconsistency in how the effect is treated. As a result the standard non-polarizable simulations are not uniformly reliable under all the solvation conditions relevant to biological applications. Particularly, the electrostatic interactions of ions given by AMBER, CHARMM, GROMOS and etc, are exaggerated in low-dielectric environment by the factor of about 2 (see figure). The data, for example, indicates to that binding strength of salt-bridges in low dielectric protein interior is essentially overestimated in simulations. We propose a solution to this issue in terms of a recently developed non-polarizable model of Molecular Dynamics in Electronic Continuum  (MDEC) [1]  . The theory also sheds new light on the long standing issue of a physical meaning of the empirical charges in the non-polarizable force fields. [1]  Leontyev I.V. and Stuchebrukhov A.A., Accounting for electronic polarization in non-polarizable force fields, Phys. Chem. Chem. Phys. 13, 2613 (2011  ). Figure: Electrostatic PMF of ionic pair in non-polar solvent (benzene).

Accounting for induced polarization in non-polarizable force fields

244th National Meeting (2012)

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