1. RT Biochemistry Section, HIV Drug Resistance Program, National Cancer Institute—Frederick, Frederick, Maryland 21702, United States
2. Center for Advanced Biotechnology and Medicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
3. NIH Chemical Genomics Center, Rockville, Maryland 20850, United States
4. Molecular Discovery Program, National Cancer Institute—Frederick, Frederick, Maryland 21702, United States