Generalized image charge solvation model for electrostatic interactions in molecular dynamics simulations of aqueous solutions

Abstract

This paper extends the image charge solvation model (ICSM) [J. Chem. Phys. 131, 154103 (2009)], a hybrid explicit/implicit method to treat electrostatic interactions in computer simulations of biomolecules formulated for spherical cavities, to prolate spheroidal and triaxial ellipsoidal cavities, designed to better accommodate non-spherical solutes in molecular dynamics (MD) simulations. In addition to the utilization of a general truncated octahedron as the MD simulation box, central to the proposed extension is an image approximation method to compute the reaction field for a point charge placed inside such a non-spherical cavity by using a single image charge located outside the cavity. The resulting generalized image charge solvation model (GICSM) is tested in simulations of liquid water, and the results are analyzed in comparison with those obtained from the ICSM simulations as a reference. We find that, for improved computational efficiency due to smaller simulation cells and consequently a less number of explicit solvent molecules, the generalized model can still faithfully reproduce known static and dynamic properties of liquid water at least for systems considered in the present paper, indicating its great potential to become an accurate but more efficient alternative to the ICSM when bio-macromolecules of irregular shapes are to be simulated.

Free energies of solvation in the context of protein folding: Implications for implicit and explicit solvent models

“…Finally, alternatives to continuum implicit solvent models exist, mainly in the form of hybrid models and molecular integral equation approaches, most prominently 3D‐reference site interaction models (RISMs), that more naturally avoid many of the assumptions of continuum approaches. While these have generally been too slow to provide much advantage over explicit models in the context of simulation, recent advances in hybrid models (both in the traditional explicit‐continuum implicit methods and in lattice methods) and in 3D‐RISMs are making them viable alternatives …”

Toward the correction of effective electrostatic forces in explicit-solvent molecular dynamics simulations: restraints on solvent-generated electrostatic potential and solvent polarization

“…The correction scheme mentioned above has proven very useful in the past [ 65 , 66 , 69 , 70 ]. Concerning future developments, it is likely that increases in computational efficiency [ 71 – 73 ] and advances in multiscale simulation methodologies [ 74 – 80 ] will, in the long run, allow for the simulation of macroscopic nonperiodic systems with Coulombic electrostatic interactions, or electrostatic interactions truncated at sufficiently large distances, such that the entire effective interaction range of ionic solutes is encompassed in the simulated system. Since electrostatic interactions are decaying extremely slowly, this range is vast and extends to about 34 nm for a sodium ion in water [ 58 ].…”

Solutions for the electric potential and field distribution in cylindrical core-shell nanoparticles using the image charge method

“…6 In particular, image charges play an important role in charge transport through molecules and single-molecule junctions, the electrostatic interactions in computer simulations of biomolecules, the surface tension of electrolyte solutions and the adsorption of polyelectrolytes. [7][8][9] So far, only a few of researches were investigated the method of image charges to study of cylindrical structures. For example, an analytical expression for the electric potential produced by a point charge located inside and outside of a cylindrical pore studied by Cui. 10 Also, Xu et al studied reaction fields due to a point charge in a hybrid ion-channel model using the IC method.…”