An in vitro transversion by a mutationally altered T4-induced DNA polymerase

Abstract

In a reaction in which poly dC serves as template, highly purified T4 DNA polymerase has been shown to incorporate dTTP into poly dG, at a level ( T G ) of 10 −5 to 10 −6. The polymerase from a temperature-sensitive mutagenic strain of T4 with a mutation in the structural gene for DNA polymerase, substitutes T for G at a frequency about fourfold higher than the wild-type enzyme. The error frequency for both enzymes depends on dTTP and dGTP concentrations and can be increased about 5- to 20-fold by the substitution of manganese for magnesium in the reaction.