1. RIKEN SPring‐8 Center, Harima Institute, 1‐1‐1 Kouto, Sayo, Hyogo 679‐5148, Japan
2. Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka 560‐0043, Japan
3. Genomic Sciences Center, Yokohama Institute, RIKEN, 1‐7‐22 Suehiro‐cho, Tsurumi‐ku, Yokohama 230‐0045, Japan
4. Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 7‐3‐1 Hongo, Bunkyo‐ku, Tokyo 113‐0033, Japan