Hydration phenomena, classical electrostatics, and the boundary element method

A formalism for a computational treatment of the polarization of a solvent containing an electrolyte and of polar solutes immersed in it is presented. The solvent is modeled as a continuum dielectric. Polarization effects are represented by a polarization charge density at the dielectric boundaries, by induced dipoles at the polarizable atoms of the solute, and by the Boltzmann distribution of ions around the solute. Calculations performed for the C-peptide of the ribonuclease suggest that the main-chain electrostatics contributes about half of the total energy driving the helix-coil transition and that interactions of charged groups with the main chain of the helix can be dominated by local effects, and not by the «helix dipole». Calculations of the ionic atmosphere around rodlike polyelectrolytes with helical distribution of charge reveal dramatic variations in the potentials and the distribution of counterions and may allow evaluation of the role of hydration and the counterions in stabilization of different forms of DNA