Institute for Protein Research, Osaka University 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan Biomolecular Engineering Research Institute 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan Osaka National Research Institute AIST 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan (At 1998-05-22)
