1. Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, 1-8-31, Ikeda, Osaka 563-8577, Japan
2. Biostructural Mechanism Laboratory, RIKEN SPring-8 Center, 1-1-1, Sayo, Hyogo 679-5148, Japan
3. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Sendai, Miyagi 980-8577, Japan
4. Advanced Electron Microscope Development Unit, RIKEN-JEOL Collaboration Center, RIKEN Baton Zone Program, 1-1-1, Sayo, Hyogo 679-5148, Japan