Mechanism of double-base lesion bypass catalyzed by a Y-family DNA polymerase

Nucleic Acids Res. 2008 Jul;36(12):3867-78. doi: 10.1093/nar/gkn309. Epub 2008 May 22.


As a widely used anticancer drug, cis-diamminedichloroplatinum(II) (cisplatin) reacts with adjacent purine bases in DNA to form predominantly cis-[Pt(NH(3))(2){d(GpG)-N7(1),-N7(2)}] intrastrand cross-links. Drug resistance, one of the major limitations of cisplatin therapy, is partially due to the inherent ability of human Y-family DNA polymerases to perform translesion synthesis in the presence of DNA-distorting damage such as cisplatin-DNA adducts. To better understand the mechanistic basis of translesion synthesis contributing to cisplatin resistance, this study investigated the bypass of a single, site-specifically placed cisplatin-d(GpG) adduct by a model Y-family DNA polymerase, Sulfolobus solfataricus DNA polymerase IV (Dpo4). Dpo4 was able to bypass this double-base lesion, although, the incorporation efficiency of dCTP opposite the first and second cross-linked guanine bases was decreased by 72- and 860-fold, respectively. Moreover, the fidelity at the lesion decreased up to two orders of magnitude. The cisplatin-d(GpG) adduct affected six downstream nucleotide incorporations, but interestingly the fidelity was essentially unaltered. Biphasic kinetic analysis supported a universal kinetic mechanism for the bypass of DNA lesions catalyzed by various translesion DNA polymerases. In conclusion, if human Y-family DNA polymerases adhere to this bypass mechanism, then translesion synthesis by these error-prone enzymes is likely accountable for cisplatin resistance observed in cancer patients.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Antineoplastic Agents / therapeutic use
  • Catalysis
  • Cisplatin / metabolism*
  • Cisplatin / therapeutic use
  • DNA / biosynthesis
  • DNA / chemistry
  • DNA Damage*
  • DNA Polymerase beta / metabolism*
  • Dinucleoside Phosphates / metabolism*
  • Drug Resistance, Neoplasm
  • Kinetics
  • Nucleotides / metabolism
  • Sulfolobus solfataricus / enzymology


  • Antineoplastic Agents
  • Dinucleoside Phosphates
  • Nucleotides
  • cisplatin-deoxy(guanosine monophosphate guanosine) adduct
  • DNA
  • DNA Polymerase beta
  • Cisplatin