1. Department of Infectious Diseases, Kumamoto University School of Medicine, Kumamoto, Japan
2. Department of Hematology, Kumamoto University School of Medicine, Kumamoto, Japan
3. Experimental Retrovirology Section, HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
4. Protein Crystal Analysis Division, Japan Synchrotron Radiation Research Institute, Hyogo, Japan
5. Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
6. Department of Medicinal Chemistry, Purdue University, West Lafayette, Indiana, USA
7. National Center for Global Health and Medicine Research Institute, Tokyo, Japan