1. Center for Advanced Biotechnology and Medicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, Center for Molecular Design, Janssen Pharmaceutica NV, Vosselaar, Belgium, Janssen Research Foundation, Spring House, Pennsylvania, Tibotec, 2800 Mechelen, Belgium, and HIV Drug Resistance Program, NIH National Cancer InstituteFrederick, Frederick, Maryland 21702