A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Department of Biochemistry, Chemistry, and Pharmacology, Vanderbilt Institute of
Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN
37232, U.S.A. Corresponding authors. E-mails: craig.duvall@vanderbilt.edu and larry.marnett@vanderbilt.edu