Library of cumulative atomic multipole moments: II. neutral and charged amino acids

Cumulative atomic multipole moments (CAMM) for 28 neutral and charged forms of naturally occurring amino acids have been obtained from ab initio LCAO-MO-SCF wave functions using the all valence MODPOT basis set with nonempirical effective core model potentials. CAMMS provide a compact and condensed representation of the molecular charge distribution at atomic resolution. They may be used to obtain satisfactory nonempirical estimates of anisotropic properties of various biomolecules that are responsible for their specific interactions, i.e., molecular electrostatic potentials, electric fields, field gradients, etc., as well as intermolecular interaction energies between polar and/or charged constituents. To facilitate calculations for large proteins, we present in this paper CAMMS for all neutral and charged forms of amino acids to supplement our previously published data for nucleic acid bases. The utility of this part of our data base has been demonstrated by calculation of histidine (HIS64) pK shifts resulting from single amino acid substitutions in several subtilisine mutant enzymes engineered by site-directed mutagenesis technique.