Institution: | From the ‡Department of Biochemistry and Molecular Biology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614, ;the §Center for Retrovirus Research and Comprehensive Cancer Center, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, and ;the ¶Departments of Biochemistry and Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232 |