1. Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
2. Biomacromolecules Research Team, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
3. RIKEN Center for Biosystems Dynamics Research, Laboratory for Cellular Structural Biology, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan