1. Department of Chemistry and Department of Medicinal Chemistry, Purdue University, West Lafayette, IN 47907, USA
2. Departments of Biology and Chemistry, Molecular Basis of Disease, Georgia State University, Atlanta, GA 30303, USA
3. Departments of Hematology and Infectious Diseases, Kumamoto University School of Medicine, Kumamoto 860-8556, Japan
4. Experimental Retrovirology Section, HIV and AIDS Malignancy Branch, National Cancer Institute, Bethesda, MD 20892, USA
5. Center for Clinical Sciences, National Center for Global Health and Medicine, Shinjuku, Tokyo 162-8655, Japan