Proofreading of a mutagenic nucleotide, N4-aminodeoxycytidylic acid, by Escherichia coli DNA polymerase I

Biochem Biophys Res Commun. 1987 Feb 27;143(1):104-9. doi: 10.1016/0006-291x(87)90636-x.

Abstract

N4-Aminodeoxycytidine triphosphate, a putative metabolite of N4-aminocytidine which is a potent mutagen, is incorporated, in vitro, into polynucleotides in place of dCTP and at a much lesser extent, but significantly, in place of dTTP by E. coli DNA polymerase I large fragment. The activity of the polymerase to proofread this unnatural nucleotide has now been investigated. The results indicate that the 3'-5' exonuclease in the polymerase recognizes N4-aminocytosine as an incorrect base when N4-aminocytosine is incorporated opposite adenine but the enzyme cannot distinguish N4-aminocytosine from cytosine when it is incorporated opposite guanine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA Polymerase I / metabolism*
  • Deoxycytosine Nucleotides / metabolism*
  • Escherichia coli / enzymology
  • Escherichia coli / genetics*
  • Kinetics
  • Mutagens / metabolism*
  • Substrate Specificity
  • Templates, Genetic
  • Tritium

Substances

  • Deoxycytosine Nucleotides
  • Mutagens
  • Tritium
  • N(4)-amino-2'-deoxycytidine triphosphate
  • DNA Polymerase I