1Department of Biochemistry Miyazaki Medical College, Kiyotake, Miyazaki 889-16, Japan
2Department of Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108, Japan
3Department of Molecular Microbiology, Research Institute for Microbial Diseases, Osaka University, Osaka 565, Japan
4Kanonji Institute, the Research Foundation for Microbial Diseases of Osaka University, Kanonji, Kugawa 768, Japan