1. United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland 21702
2. Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198
3. Department of Chemistry and Combinatorial Chemistry Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
4. Developmental Therapeutics Program, National Cancer Institute at Frederick, Frederick, Maryland 21702
5. Target Structure-Based Drug Discovery Group, SAIC-Frederick, Inc., National Cancer Institute at Frederick, Frederick, Maryland 21702