[1] Univ Calif San Francisco, Dept Pharmaceut Chem, San Francisco, CA 94143 USA
[2] Univ Calif San Francisco, Tetrad Grad Program, San Francisco, CA 94143 USA
[3] Univ Calif San Francisco, Dept Cellular & Mol Pharmacol, San Francisco, CA 94143 USA
[4] Univ Calif San Francisco, Dept Biochem & Biophys, San Francisco, CA 94143 USA
[5] Howard Hughes Med Inst, San Francisco, CA 94143 USA