1. Contribution from the Pensacola Christian College, Department of Basic Sciences and Engineering, 250 Brent Lane Pensacola, Florida 32503, Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602-2525, and Drug Design & Discovery Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, CAS Shanghai 200031 P. R. China