1. Key Laboratory of Pesticide & Chemical Biology, College of Chemistry, Ministry of Education, Central China Normal University, Wuhan 430079, P.R. China, MOE Key Laboratory of Bioinformatics, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, P.R. China, and Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 725 Rose Street, Lexington, Kentucky 40536