1. Department of Chemistry University of California, Irvine Irvine, CA 92697 (USA)
2. Department of Medical Biochemistry School of Pharmaceutical Sciences University of Shizuoka 52‐1 Yada, Shizuoka 422‐8526 (Japan)
3. Department of Biomolecular Engineering Tokyo Institute of Technology 4259 Nagatsuda, Midoriku, Yokohama 226‐8501 (Japan)