[1] Structural Biology Center, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
[2] Research Center for Allergy and Immunology, RIKEN, Yokohama, Kanagawa 230-0045, Japan
[3] Department of Genetics, School of Life Science, The Graduate University for Advanced Studies (Sokendai), Mishima, Shizuoka 411-8540, Japan
[4] Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Nagatsuta, Midori, Yokohama, Kanagawa 226-8501, Japan