title: A novel activity of E. coli uracil DNA N-glycosylase excision of isodialuric acid (5,6-dihydroxyuracil), a major product of oxidative DNA damage, from DNA.
abstract: We describe a novel activity of E. coli uracil DNA N-glycosylase (UNG) that excises isodialuric acid from DNA. Isodialuric acid is formed in DNA as a major oxidative product of cytosine. DNA substrates, which were prepared by gamma-irradiation, were incubated with UNG. Following precipitation of DNA, analyses of pellets and supernatant fractions by gas chromatography/mass spectrometry showed an efficient excision of isodialuric acid from DNA by UNG. None of the other 15 identified DNA base lesions was excised. The excision of isodialuric acid indicates that the non-aromaticity of a substrate may not be a limiting factor for UNG.
authors.affiliation: Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
authors.forename: T H
authors.initials: TH
authors.lastname: Zastawny
authors.forename: P W
authors.initials: PW
authors.lastname: Doetsch
authors.forename: M
authors.initials: M
authors.lastname: Dizdaroglu
mesh_terms: D003596:Cytosine / Q000378:metabolism; D004247:DNA / Q000378:metabolism* / Q000528:radiation effects; D004249:DNA Damage; D045647:DNA Glycosylases; D004926:Escherichia coli / Q000201:enzymology*; D005609:Free Radicals; D005720:Gamma Rays; D007700:Kinetics; D009699:N-Glycosyl Hydrolases / Q000378:metabolism*; D010084:Oxidation-Reduction; D013379:Substrate Specificity; D014498:Uracil / Q000031:analogs & derivatives* / Q000378:metabolism; D051981:Uracil-DNA Glycosidase
chemical_list: D005609:Free Radicals; C093681:isodialuric acid; D014498:Uracil; D003596:Cytosine; D004247:DNA; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; D051981:Uracil-DNA Glycosidase