title: Mechanisms of free radical-induced damage to DNA.
abstract: Endogenous and exogenous sources cause free radical-induced DNA damage in living organisms by a variety of mechanisms. The highly reactive hydroxyl radical reacts with the heterocyclic DNA bases and the sugar moiety near or at diffusion-controlled rates. Hydrated electron and H atom also add to the heterocyclic bases. These reactions lead to adduct radicals, further reactions of which yield numerous products. These include DNA base and sugar products, single- and double-strand breaks, 8,5'-cyclopurine-2'-deoxynucleosides, tandem lesions, clustered sites and DNA-protein cross-links. Reaction conditions and the presence or absence of oxygen profoundly affect the types and yields of the products. There is mounting evidence for an important role of free radical-induced DNA damage in the etiology of numerous diseases including cancer. Further understanding of mechanisms of free radical-induced DNA damage, and cellular repair and biological consequences of DNA damage products will be of outmost importance for disease prevention and treatment.
authors.affiliation: Biochemical Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA. miral@nist.gov
authors.forename: Miral
authors.initials: M
authors.lastname: Dizdaroglu
authors.forename: Pawel
authors.initials: P
authors.lastname: Jaruga
mesh_terms: D000818:Animals; D004247:DNA / Q000378:metabolism*; D004249:DNA Damage / Q000187:drug effects*; D005609:Free Radicals / Q000494:pharmacology*; D006801:Humans; D018384:Oxidative Stress
chemical_list: D005609:Free Radicals; D004247:DNA