Radiation-induced damage to DNA: mechanistic aspects and measurement of base lesions

Abstract

Emphasis has been placed in the present survey on mechanistic aspects of the radiation-induced decomposition of the guanine moiety of DNA and model compounds. An almost complete description of the radical reactions induced by both OH radicals (indirect effects) and one-electron oxidation (direct effects) in aerated aqueous solution is now possible. This was inferred from both earliest investigations of the transient radicals of these reactions and detailed structural determination of the final decomposition products. Information is also provided on several tandem lesions whose formation results from one initial radical event involving either the sugar moiety or the base residue of nucleosides. It should be noted that there is a paucity of information on the radiation-induced formation of base damage within cellular DNA. A critical evaluation of the available methods aimed at monitoring the levels of oxidative base damage to cellular DNA is made in the second part of the review article.