Fig. 4.

Increased mismatch extension capacity of Polε-P301R. a DNA polymerase activity was assayed on P51T/T80 oligonucleotide substrate containing a terminal G-T mismatch, and the fraction of primer extended (≥52 nt) was quantified. The polymerase and DNA substrate concentrations are as in Fig. 3a. Representative of seven independent experiments. b Polε variants were incubated with the P51T/T80 substrate for 30 min, and relative efficiency of mismatch extension vs. proofreading was determined by BsaJI digestion of the reaction products. The appearance of 51-nt restriction fragment indicates that the mismatch has been corrected by the polymerase. The 80-nt fragments resistant to BsaJI digestion represent products of mismatch extension. Representative of two independent experiments. Source data are provided in a Source Data file