1. Department of Pharmacology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6084 (P.H.A., B.K.K., F.J.P.); Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905 (W.D.B.); Hormel Institute, University of Minnesota, Austin, Minnesota 55912 (H.L.B., C.M.J.); and Department of Chemistry, University of Georgia, Athens, Georgia 30602-2556 (R.A.D.)