Affiliation: | 1. Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo‐ku, Tokyo 113‐0033 (Japan), Fax: (+81)?3‐5684‐5206;2. Institute of Microbial Chemistry, Tokyo, Kamiosaki 3‐14‐23, Shinagawa‐ku, Tokyo 141‐0021 (Japan), Fax: (+81)?3‐3447‐7779 |