Generation and characterization of a nucleoside radical resulting from dissociative electron attachment

TOXI 80

Suaad Abdallah, saabdall@oakland.edu, CherylAnn Trzasko, ctrzasko@hotmail.com, and Amanda C. Bryant-Friedrich, friedric@oakland.edu. Department of Chemistry, Oakland University, 2200 Squirrel Road, Rochester, MI 48309
The mutagenic effects of ionizing radiation can be largely attributed to secondary electrons. Through dissociative electron attachment, these secondary low-energy electrons (0-20 eV) add to the sugar phosphate backbone of DNA. This process leads to the formation of sugar, base, and phosphate radicals ultimately resulting in single and double strand breaks. When this attachment occurs at a nucleotide phosphate, cleavage of an associated C-O bond is the result and formation of a C3'- or C5'-nucleotide radical follows. We have synthesized protected 3'-deoxy-3'-(pivaloyl)thymidine as a precursor of the 2',3'-dideoxythymidinyl radical. This intermediate has been photolytically generated and its structure, reactivity and fate will be investigated using a variety of techniques including ESR and hydrogen atom trapping experiments. The nature of the products that result from the degradation of this radical will be determined.