1. Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan, School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K., and Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, University of Dundee, Dundee DDI 5EH, U.K.