A dielectric continuum model of solvation for complex solutes

Abstract

In the past, we have introduced a novel method to describe the solvation of complex solutes in computer simulation. This class of techniques represent the solvent with a dielectric continuum approach and enforces the requirement that the theory yields an exact description of the macroscopic laws of electrostatics. In our approach, the solvent is described by dielectric continuum and the interaction between the solvent and the molecular degrees of freedom is handled by means of a polarization density free energy functional which is minimum at electrostatic equilibrium. After a pseudospectral expansion of the polarization and a discretization of the functional, we construct the equations of motion for the system based on a Car–Parrinello technique. In the limit of the adiabatic evolution of the polarization field variables, our method provides the solution of the dielectric continuum problem “on the fly”, while the molecular coordinates are propagated. The computational efficiency of the method has also been tested against more complex solutes such as proteins. We show that how our implicit solvent molecular dynamics method can be successfully applied to hydrated biomolecules, with low cost compared to free energy simulations with explicit solvent.