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