title: Biochemical properties of Saccharomyces cerevisiae DNA polymerase IV.
abstract: Although mammals encode multiple family X DNA polymerases implicated in DNA repair, Saccharomyces cerevisiae has only one, DNA polymerase IV (pol IV). To better understand the repair functions of pol IV, here we characterize its biochemical properties. Like mammalian pol beta and pol lambda, but not pol mu, pol IV has intrinsic 5'-2-deoxyribose-5-phosphate lyase activity. Pol IV has low processivity and can fill short gaps in DNA. Unlike the case with pol beta and pol lambda, the gap-filling activity of pol IV is not enhanced by a 5'-phosphate on the downstream primer but is stimulated by a 5'-terminal synthetic abasic site. Pol IV incorporates rNTPs into DNA with an unusually high efficiency relative to dNTPs, a property in common with pol mu but not pol beta or pol lambda. Finally, pol IV is highly inaccurate, with an unusual error specificity indicating the ability to extend primer termini with limited homology. These properties are consistent with a possible role for pol IV in base excision repair and with its known role in non-homologous end joining of double strand breaks, perhaps including those with damaged ends.
authors.affiliation: Laboratory of Molecular Genetics and Laboratory of Structural Biology, NIEHS, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709, USA.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Bebenek
authors.forename: Miguel
authors.initials: M
authors.lastname: Garcia-Diaz
authors.forename: Steven R
authors.initials: SR
authors.lastname: Patishall
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Kunkel
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D019951:DNA Polymerase beta; D004260:DNA Repair; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D007763:Lac Operon; D008969:Molecular Sequence Data; D009154:Mutation; D019761:Phosphorus-Oxygen Lyases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012265:Ribonucleotides / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D004271:DNA, Fungal; D011994:Recombinant Proteins; D012265:Ribonucleotides; D029701:Saccharomyces cerevisiae Proteins; C423906:5'-deoxyribose phosphate lyase; D019951:DNA Polymerase beta; D004259:DNA-Directed DNA Polymerase; C084892:POL4 protein, S cerevisiae; D019761:Phosphorus-Oxygen Lyases