Electronic Properties for Medicine Inhibiting Cancer Metastasis (1) : Molecular Orbital Calculations for Physiological Substance Bikunin

Abstract

The electronic properties of bikunin, which is a reaction part of a chimeric protein inhibiting cancer metastasis, were investigated by semiempirical molecular orbital (MO) calculations. From the distributions of highest occupied MO (HOMO) and lowest unoccupied MO (LUMO), the chemically reactive part of bikunin was specified to be the experimentally proposed site. Furthermore, some amino acids existing around the reaction part in bikunin were mutated by other amino acid, and the effect of mutations on the HOMO and LUMO distributions was investigated in detail by the MO calculations. Based on these results, we predicted which amino acid in bikunin is important for the chemical reaction between bikunin and cancer.