1. Department of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
2. National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States
3. Protein Structure and X-ray Crystallography Laboratory, Structural Biology Center, University of Kansas, Lawrence, Kansas 66045, United States
4. New York Structural Biology Center, NSLS-II, Upton, New York 11973, United States
5. National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892, United States