Parameterization of the hydration free energy computations for organic solutes in the framework of the implicit solvent model with the nonuniform dielectric function

Abstract An earlier developed Smooth Boundary Continuum Model (SBCM) which allows to consider the solution in inhomogeneous media has been parameterized for the calculation of hydration free energy. The traditional (for implicit models of solvent influence) decomposition Δ G solv on polar, nonpolar and hydrophobic components for implicit models of solvent has been used. The peculiarity of SBCM appears as a position-dependent dielectric permittivity function, which is applied for a computation of the electrostatic component of Δ G solv in the frame of solving the pertaining Poisson equation. By this means non-uniformity of medium environment for a solute particle can be simulated. This feature distinguishes the present approach from its conventional counterparts based on standard uniform electrostatic schemes. Two hundred and three molecular species, covering most important classes of neutral organic molecules, have been considered for the parameterization. The comparison of calculated and experimental Δ G solv for these species results the root mean square deviation value that is quite comparable with literature data and equal to 0.76 kcal/mol. The current status and the perspectives of developing the SBCM is discussed.