title: Formation of isodialuric acid lesion within DNA oligomers via one-electron oxidation of 5-hydroxyuracil: characterization, stability and excision repair.
abstract: 5-Hydroxyuracil is a major oxidized nucleobase that can be generated by the action of (*)OH radical and one-electron oxidants. The latter modified base that exhibits a low ionization potential is highly susceptible to further degradation upon exposure to various oxidants. Emphasis was placed in this work on the formation and characterization of one-electron oxidation products of 5-hydroxyuracil within DNA fragments of defined sequence. For this purpose, 5-hydroxyuracil containing single- and double-stranded oligonucleotides of various lengths were synthesized and then exposed to the oxidizing action of iridium salts. Isodialuric acid was found to be formed almost quantitatively by a one-electron oxidation mechanism for which relevant information was inferred from a freeze-quenched ESR study. Information on the stability of isodialuric acid thus formed and its conversion products in aqueous solutions was also gained from experiments performed at acidic, neutral and alkali pH's. Moreover, biochemical features dealing with the substrate specificity of several bacterial and yeast base excision repair enzymes to remove isodialuric acid from site-specifically modified DNA fragments were determined.
authors.affiliation: Laboratoire des Lésions des Acides Nucléiques, Département de Recherche Fondamentale sur la Matière Condensée Service de Chimie Inorganique et Biologique, UMR E3 CEA-UJF, CEA-Grenoble, F-38054 Grenoble Cedex 9, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Simon
authors.forename: Didier
authors.initials: D
authors.lastname: Gasparutto
authors.forename: Serge
authors.initials: S
authors.lastname: Gambarelli
authors.forename: Christine
authors.initials: C
authors.lastname: Saint-Pierre
authors.forename: Alain
authors.initials: A
authors.lastname: Favier
authors.forename: Jean
authors.initials: J
authors.lastname: Cadet
mesh_terms: D004249:DNA Damage; D045647:DNA Glycosylases / Q000378:metabolism; D004260:DNA Repair; D004578:Electron Spin Resonance Spectroscopy; D004583:Electrons; D006827:Hydantoins / Q000737:chemistry; D009705:Nucleosides; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D010429:Pentoses / Q000737:chemistry; D013379:Substrate Specificity; D014498:Uracil / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism
chemical_list: C512425:1-(2-deoxypentofuranosyl)isodialuric acid; C505955:5-hydroxy-1-(2'-deoxyribofuranosyl)hydantoin; D006827:Hydantoins; D009705:Nucleosides; D009838:Oligodeoxyribonucleotides; D010429:Pentoses; C093681:isodialuric acid; C045975:5-hydroxyuracil; D014498:Uracil; D045647:DNA Glycosylases