We are grateful to the NIH-NIGMS (R01 GM090007), Boehringer Ingelheim, DuPont, Eli Lilly, Amgen, AstraZeneca, Roche, the A. P. Sloan Foundation, the S. T. Li Foundation, the Dreyfus Foundation, the University of California, Los Angeles, Bristol-Myers Squibb (A.D.H.), the NSF (N.A.W., DGE-1144087), and the Foote Family (A.D.H. and E.D.S.) for financial support. We thank the Garcia-Garibay laboratory (UCLA) for access to instrumentation and Dr. John Greaves (UC Irvine) for mass spectra. These studies were supported by shared instrumentation grants from the NSF (CHE-1048804) and the National Center for Research Resources (S10RR025631).