ELECTROSTATIC PROTEIN-PROTEIN INTERACTIONS - COMPARISON OF POINT-DIPOLE AND FINITE-LENGTH DIPOLE POTENTIALS OF MEAN FORCE

Based on summation of Coulombic interactions, a model is developed for finite-length dipole potentials of mean force in a salt-free dielectr ic continuum. Point-dipole and finite-length dipole potentials of mean force are compared for protein-protein interactions using parameters for bovine alpha-chymotrypsin. The two approximations made in the comm only used analytical point-dipole potentials of mean force are not val id at distances near contact. Relative to the finite-length dipole mod el, the high-temperature approximation overpredicts, and the point-dip ole approximation underpredicts charge-dipole and dipole-dipole attrac tions. (C) 1996 Academic Press, Inc.