title: An intrinsic 5'-deoxyribose-5-phosphate lyase activity in DNA polymerase beta from Leishmania infantum supports a role in DNA repair.
abstract: Leishmania infantum is a parasitic protozoan which infects humans. This paper reports the expression in Escherichia coli and purification of the L. infantum gene product (AF182167), as well as its characterization as a DNA polymerase beta (Polbeta)-like, template-dependent DNA repair enzyme, with a metal preference for Mn2+ over Mg2+. As is the case with mammalian Polbeta and DNA polymerase lambda (Pollambda), L. infantum DNA polymerase beta (Li Polbeta) prefers gapped-DNA substrates having a 5'-phosphate end, in agreement with its role in DNA repair reactions. Purified Li Polbeta also displayed a 5'-deoxyribose-5-phosphate (dRP) lyase activity, consistent with a beta-elimination mechanism. The concerted action of dRP lyase and DNA polymerization activities of Li Polbeta on a uracil-containing DNA suggests its participation in "single-nucleotide" base excision repair (BER). Analysis of Li Polbeta DNA polymerization activity at different stages of the L. infantum infective cycle supports a role for Li Polbeta in nuclear DNA repair after the oxidative damage occurring inside the macrophage.
authors.affiliation: Centro de Investigaciones Biológicas, CSIC, c/Ramiro de Maeztu 9, 28040 Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Alonso
authors.forename: Gloria
authors.initials: G
authors.lastname: Terrados
authors.forename: Angel J
authors.initials: AJ
authors.lastname: Picher
authors.forename: Rafael
authors.initials: R
authors.lastname: Giraldo
authors.forename: Luis
authors.initials: L
authors.lastname: Blanco
authors.forename: Vicente
authors.initials: V
authors.lastname: Larraga
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019951:DNA Polymerase beta / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic; D002479:Inclusion Bodies / Q000235:genetics; D018314:Leishmania infantum / Q000201:enzymology* / Q000502:physiology; D008274:Magnesium / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D008969:Molecular Sequence Data; D019761:Phosphorus-Oxygen Lyases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D011994:Recombinant Proteins; D008345:Manganese; C423906:5'-deoxyribose phosphate lyase; D019951:DNA Polymerase beta; D019761:Phosphorus-Oxygen Lyases; D008274:Magnesium