1. Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan, Institute for Solid State Physics, University of Tokyo, Tokai, Ibaraki 319-1106, Japan, School of Pharmaceutical Science, Toho University, Funabashi, Chiba 247-8510, Japan, and Research Institute of Biological Materials, Tohma, Nara 639-2154, Japan