1. Departments of Chemistry, Medicine, Biochemistry, and Pathobiology, University of Washington, Seattle, Washington 98195, Department of Molecular Biology and Microbiology, University of Central Florida, Orlando, Florida 32826, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, New Jersey 08543-4000, Department of Chemistry, Yale University, New Haven, Connecticut 06520, Schering-Plough Research Institute, Kenilworth, New Jersey 07033, and Departments of Oncology and Biochemisty & Molecular...