1. Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya 464−8602, Japan, Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, 3−14−1 Hiyoshi, Yokohama 223−8522, Japan, and Research Institute for Clinical Oncology, Saitama Cancer Center, Ina, Kitaadachi-gun, Saitama 362−0806, Japan