1. A.B. Hancock Jr. Memorial Laboratory for Cancer Research, Departments
of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute
of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram
Cancer Center, ‡Department of Chemistry, and §Mass Spectrometry Research Core, Vanderbilt
University, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States