The efficiency and fidelity of translesion synthesis past cisplatin and oxaliplatin GpG adducts by human DNA polymerase beta

J Biol Chem. 2000 Apr 28;275(17):13017-25. doi: 10.1074/jbc.275.17.13017.

Abstract

DNA polymerase beta (pol beta) is the only mammalian DNA polymerase identified to date that can catalyze extensive bypass of platinum-DNA adducts in vitro. Previous studies suggest that DNA synthesis by pol beta is distributive on primed single-stranded DNA and processive on gapped DNA. The data presented in this paper provide an analysis of translesion synthesis past cisplatin- and oxaliplatin-DNA adducts by pol beta functioning in both distributive and processive modes using primer extension and steady-state kinetic experiments. Translesion synthesis past Pt-DNA adducts was greater with gapped DNA templates than with single-stranded DNA templates. In the processive mode pol beta did not discriminate between cisplatin and oxaliplatin adducts, while in the distributive mode it displayed about 2-fold increased ability for translesion synthesis past oxaliplatin compared with cisplatin adducts. The differentiation between cisplatin and oxaliplatin adducts resulted from a K(m)-mediated increase in the efficiency of dCTP incorporation across from the 3'-G of oxaliplatin-GG adducts. Rates of misincorporation across platinated guanines determined by the steady-state kinetic assay were higher in reactions with primed single-stranded templates than with gapped DNA and a slight increase in the misincorporation of dTTP across from the 3'-G was found for oxaliplatin compared with cisplatin adducts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Base Sequence
  • Cisplatin / pharmacology*
  • DNA Adducts / metabolism*
  • DNA Polymerase beta / metabolism*
  • DNA Primers / metabolism
  • DNA Repair*
  • DNA Replication*
  • Deoxycytosine Nucleotides / metabolism
  • Humans
  • Kinetics
  • Molecular Sequence Data
  • Organoplatinum Compounds / pharmacology*
  • Oxaliplatin
  • Recombinant Proteins / metabolism
  • Thymine Nucleotides / metabolism
  • Time Factors

Substances

  • Antineoplastic Agents
  • DNA Adducts
  • DNA Primers
  • Deoxycytosine Nucleotides
  • Organoplatinum Compounds
  • Recombinant Proteins
  • Thymine Nucleotides
  • Oxaliplatin
  • 2'-deoxycytidine 5'-triphosphate
  • DNA Polymerase beta
  • Cisplatin
  • thymidine 5'-triphosphate