1. Department of Chemistry, Faculty of Science, Shizuoka University, Shizuoka 422-8529
2. Graduate School of Integrated Science, Yokohama City University, Tsurumi-ku, Yokohama, Kanagawa 230-0045
3. Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
4. Genome Damage and Stability Centre, University of Sussex, Brighton BN1 9RQ, United Kingdom