1. Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
2. Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095
3. Institute of Genomics and Proteomics, David Geffen School of Medicine at the University of California, Los Angeles, California 90095
4. Department of Biological Chemistry, David Geffen School of Medicine at the University of California, Los Angeles, California 90095