1. DNA Research Center,National Institute of Genetics, and School of Life Science, The Graduate University for Advanced Studies, Mishima, Japan 411.
2. Department of Electrical Engineering and Electronics, Seikei University, Tokyo, Japan 103.
3. Advance Company, Tokyo, Japan 103
4. Department of Biochemistry, Queen's Medical Center, Nottingham University, Nottingham, UK NG7 2UH.