ASFV DNA polymerase extends recessed DNAs with catalytic efficiencies outperforming those exerted on gapped DNA substrates.

Abstract

The DNA polymerase from african swine fever virus (ASFV Pol X), lacking both 8 kDa and thumb domains, is the smallest enzyme featuring competence in DNA extension. Here we show that ASFV Pol X features poor filling activity of DNA gaps consisting of 15 bases, and exerts a more efficient action at the expense of DNA substrates containing a recessed end of equal length. We also show that shortening the recessed end of DNA substrates decreases the rate of DNA elongation catalysed by ASFV Pol X. Finally, by means of stopped-flow experiments we were able to determine that DNA binding is a step responsible for restraining the efficiency of ASFV Pol X catalytic action.