Structural and functional insight into mismatch extension by human DNA polymerase α.
Publication Type:Journal Article
Source:Proc Natl Acad Sci U S A, Volume 119, Issue 17, p.e2111744119 (2022)
Keywords:Catalytic Domain, DNA Polymerase I, DNA Primers, DNA Replication, Humans, Kinetics
<p>SignificanceDespite the important role of human DNA polymerase α (Polα) in genome mutagenesis, there are no structural studies of Polα infidelity. The functional studies are sparse, lack high-resolution approaches, and are performed at a low salt concentration. Here we report the structure of the human Polα catalytic domain in the complex with an incoming deoxycytidine triphosphate (dCTP) and the template:primer containing a T-C mismatch at the growing primer terminus. Pre-steady-state and binding kinetics conducted at a physiological salt concentration revealed that Polα has a remarkably lower affinity to DNA and deoxynucleotide triphosphate (dNTP) than reported previously. Strikingly, we found that the incoming dNTP plays a crucial role in Polα interaction with DNA and in discrimination against a mismatched template:primer. This work is important for understanding the mechanism of Polα infidelity and provides a foundation for future studies.</p>