1. Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA.
2. The Wistar Institute and Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
3. State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, P. R. China.
4. National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.