1. Department of Bioscience and Bioinformatics, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
2. National Institute for Nanotechnology, National Research Council of Canada, W6-010, ECERF Building, University of Alberta, 9107 116th Street, Edmonton, Alberta T6G 2V4, Canada
3. Department of Theoretical Studies, Institute for Molecular Science, Okazaki, Aichi 444-8585, Japan