1. Department of Materials Science and Engineering, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan, Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan, Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Corporation, Kyoto 606-8502, Japan, Department of Life Science and Interdisciplinary Program of Integrated Biotechnology, Sogang University, Shinsu-Dong 1, Mapo-Gu, Seoul 121-742, Korea