1. Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan, Faculty of Pharmaceutical Sciences, Teikyo University, 1091-1 Suarashi, Sagamiko, Kanagawa 199-0195, Japan, and CREST, Japan Science and Technology Agency (JST), Tokyo, Japan