1. Department of Applied Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8552, Japan, The University of Tokyo, Institute of Molecular and Cellular Biosciences, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan, and National Institute of Advanced Industrial Science and Technology (AIST), Biological Information Research Center (BIRC), Protein Network Team, Low M.W. Chemical Laboratory, AIST Tokyo Waterfront Bio-IT Research Building, 2-42 Aomi, Koto-ku, Tokyo 135-0064, Japan