1. Department of Structural Molecular Biology, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan, Department of Physical Chemistry, Kyoto Pharmaceutical University, Kyoto, Kyoto 607-8414, Japan, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan, and Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan