On the fidelity of DNA polymerase alpha: the influence of alpha-thio dNTPs, Mn2+ and mismatch repair

Nucleic Acids Res. 1985 Aug 12;13(15):5685-95. doi: 10.1093/nar/13.15.5685.


The phi X174am16 revertant system has been used to investigate the influence of alpha-thio-dNTPs and of Mn2+ on the fidelity of the 9S DNA polymerase alpha from calf thymus. Upon substituting dGTP by alpha-thio-dGTP during the in vitro replication, a nearly tenfold decrease in the frequency of G:G and G:T mispairs is observed. The formation of all other mispairs is not changed in the presence of the corresponding alpha-thio-dNTP. Mn2+ at concentrations of 0.5 mM does not influence the frequencies of the mispairs. The expression rate of errors formed during in vitro replication in the (-) strand has been determined for all mispairs detectable in the phi Xam16 system. The (-) strand expression of G:T, T:T and C:T mismatches is about 50%, whereas for A:G, G:G and C:A mismatches it is clearly below 50%. We conclude that the different base-base mismatches are repaired with different efficiencies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacteriophage phi X 174 / genetics*
  • Base Composition
  • Cattle
  • DNA Polymerase II / metabolism*
  • DNA Repair
  • DNA Replication / drug effects*
  • DNA, Viral / metabolism*
  • Deoxyguanine Nucleotides / pharmacology*
  • Diphosphates / pharmacology
  • Manganese / pharmacology*
  • Mutation
  • Structure-Activity Relationship
  • Substrate Specificity
  • Thionucleotides / pharmacology*


  • DNA, Viral
  • Deoxyguanine Nucleotides
  • Diphosphates
  • Thionucleotides
  • 2'-deoxy-6-thioguanosine 5'-triphosphate
  • Manganese
  • DNA Polymerase II