title: Excision of 5'-terminal deoxyribose phosphate from damaged DNA is catalyzed by the Fpg protein of Escherichia coli.
abstract: Homogeneous Fpg protein of Escherichia coli has DNA glycosylase activity which excises some purine bases with damaged imidazole rings, and an activity excising deoxyribose (dR) from DNA at abasic (AP) sites leaving a gap bordered by 5'- and 3'-phosphoryl groups. In addition to these two reported activities, we show that the Fpg protein also catalyzes the excision of 5'-terminal deoxyribose phosphate (dRp) from DNA, which is the principal product formed by the incision of AP endonucleases at abasic sites. Moreover, the rate of the Fpg protein catalysis for the 2,6-diamino-4-hydroxy-5-formamidopyrimidine-DNA glycosylase activity is slower than the activities excising dR from abasic sites and dRp from abasic sites preincised by endonucleases. The product released by the Fpg protein in the excision of 5'-terminal dRp from an abasic site preincised by an AP endonuclease is a single base-free unsaturated dRp, suggesting that the excision results from beta-elimination. The release of 5'-terminal dRp by crude extracts of E. coli from wild type and fpg-mutant strains shows that the Fpg protein is one of the major EDTA-resistant activities catalyzing this reaction.
authors.affiliation: Groupe Réparation des Lésions Radio et Chimio Induites, Centre National de la Recherche Scientifique URA147, Institut Gustave-Roussy, Villejuif, France.
authors.forename: R J
authors.initials: RJ
authors.lastname: Graves
authors.forename: I
authors.initials: I
authors.lastname: Felzenszwalb
authors.forename: J
authors.initials: J
authors.lastname: Laval
authors.forename: T R
authors.initials: TR
authors.lastname: O'Connor
mesh_terms: D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D004249:DNA Damage; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D043382:DNA-Formamidopyrimidine Glycosylase; D043223:Deoxyribonuclease IV (Phage T4-Induced); D004706:Endodeoxyribonucleases / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D007700:Kinetics; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000378:metabolism*; D012267:Ribosemonophosphates / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D009838:Oligodeoxyribonucleotides; D012267:Ribosemonophosphates; C031302:2-deoxyribose 1-phosphate; D004247:DNA; D004706:Endodeoxyribonucleases; D043223:Deoxyribonuclease IV (Phage T4-Induced); C468972:endonuclease IV, E coli; D009699:N-Glycosyl Hydrolases; D043382:DNA-Formamidopyrimidine Glycosylase; C468610:DNA-formamidopyrimidine glycosylase, E coli; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase