Center for Drug Design and Discovery, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China, Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, BCM-125, Houston, Texas 77030, and Department of Bioengineering, Rice University, Houston, Texas 77005 (At 2006-08-17)