1. Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, 1-18-1, Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan, Core Research for Evolutional Science and Technology of Japan Science and Technology Agency, Kawaguchi Center Building, 4-1-8 Hon-cho, Kawaguchi, Saitama 332-0012, Japan, and Pharmaceutical Research and Technology Institute, Kinki University, 3-4-1 Kowakae, Higashi-Osaka 577-8502, Japan