1. Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan, Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Japan, Kobe Pharmaceutical University, Kobe 658-8558, Japan, and Department of Materials Science and Engineering, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan