Registration, orientation, and similarity of molecular electrostatic potentials through multipole matching

Abstract

The use of a multipolar decomposition of the far electrostatic potential for the purposes of molecular field similarity comparison between structurally different molecules has been impractical because the multipolar decomposition depends on the center of expansion. That center of expansion is essentially arbitrary, which renders the multipolar coefficients to be a nonunique characterization of the field. This article provides the definition of a center of expansion at which the multipolar decomposition is unique. For the first time, it is possible to use multipolar decomposition to characterize molecular fields beyond the first term, which is invariant under translation of the center of expansion. Calculations are performed for two structurally distinct types of HIV-1 inhibitors, three non-nucleoside reverse transcriptase inhibitors, and three phospholipids using these unique multipolar descriptors. Differences and similarities in the calculated values of these descriptors will be shown to parallel the differences and similarities of molecular charge distributions. © 1996 by John Wiley & Sons, Inc.