Computational characterization of nucleotide bases: Molecular surface electrostatic potentials and local ionization energies, and local polarization energies

Electrostatic potentials and local ionization energies have been computed at the HF/6-31G* level on the molecular surfaces of the five nucleotide bases. The potentials are analyzed in terms of their most positive and negative values as well as several statistically defined quantities that reflect their patterns over the entire surface. Considerable charge separation and variability are found for all five molecules. The results are consistent with the base pairing that is known to occur. The observed reactive behavior toward electrophiles can be interpreted in terms of the complementary roles of the surface potential and the local electron lability. Local polarization energies, corresponding to a test charge being placed at specific points above the molecules, are also calculated (HF/6-31+G*), and their relationship to the local ionization energies is examined. (C) 2001 John Wiley & Sons, Inc.