title: Single-stranded oligodeoxyribonucleotides are substrates of Fpg protein from Escherichia coli.
abstract: The interaction of Escherichia coli Fpg protein, which catalyzes excision of several damaged purine bases including 8-oxoguanine (oxoG) from DNA with a set of single- (ss) and double-stranded (ds) 23-mer oligodeoxyribonucleotides (ODNs) containing 8-oxoguanine(s) at various positions, has been investigated. The affinities of different ss ODNs (KM = 0.55-1.3 microM) were shown to be 12-170 times less than those for corresponding ds ODNs (KM = 6-60 nM). Depending on the position of the oxoG within the ODNs, relative initial rates of conversion of ss substrates may be less than, comparable, or greater than those for ds ODNs. The enzyme can remove 5'-terminal oxoG from ODNs only if the 5'-end is phosphorylated. Fpg does not release oxoG residues from the ultimate and penultimate 3'-terminal positions. Duplexes containing two adjacent oxoG are poor substrates for the glycosylase.
authors.affiliation: Novosibirsk Institute of Bioorganic Chemistry, Siberian Division of the Russian Academy of Sciences, Russian Federation.
authors.forename: A A
authors.initials: AA
authors.lastname: Ishchenko
authors.forename: N V
authors.initials: NV
authors.lastname: Bulychev
authors.forename: G A
authors.initials: GA
authors.lastname: Maksakova
authors.forename: F
authors.initials: F
authors.lastname: Johnson
authors.forename: G A
authors.initials: GA
authors.lastname: Nevinsky
mesh_terms: D004247:DNA / Q000378:metabolism; D004249:DNA Damage; D004277:DNA, Single-Stranded / Q000378:metabolism*; D043382:DNA-Formamidopyrimidine Glycosylase; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D006147:Guanine / Q000031:analogs & derivatives / Q000378:metabolism; D007700:Kinetics; D009699:N-Glycosyl Hydrolases / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D004277:DNA, Single-Stranded; D029968:Escherichia coli Proteins; D009838:Oligodeoxyribonucleotides; C024829:8-hydroxyguanine; D006147:Guanine; D004247:DNA; D009699:N-Glycosyl Hydrolases; D043382:DNA-Formamidopyrimidine Glycosylase; C468610:DNA-formamidopyrimidine glycosylase, E coli