1. Laboratory of Chemical Biology, Department of Pharmacological Sciences, State University of New York at Stony Brook, Stony Brook, New York 11794-8651, Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan, and Discovery Research Institute, RIKEN, and CREST, JST, Wako, Saitama 351-0198, Japan