Structural determinant for switching between the polymerase and exonuclease modes in the PCNA-replicative DNA polymerase complex.

Abstract:

Proliferating cell nuclear antigen (PCNA) is responsible for the processivity of DNA polymerase. We determined the crystal structure of Pyrococcus furiosus DNA polymerase (PfuPol) complexed with the cognate monomeric PCNA, which allowed us to construct a convincing model of the polymerase-PCNA ring interaction, with unprecedented configurations of the two molecules. Electron microscopic analyses indicated that this complex structure exists in solution. Our structural study revealed that an interaction occurs between a stretched loop of PCNA and the PfuPol Thumb domain, in addition to the authentic PCNA-polymerase recognition site (PIP box). Comparisons of the present structure with the previously reported structures of polymerases complexed with DNA, suggested that the second interaction plays a crucial role in switching between the polymerase and exonuclease modes, by inducing a PCNA-polymerase complex configuration that favors synthesis over editing. This putative mechanism for fidelity control of replicative DNA polymerases is supported by experiments, in which mutations at the second interaction site caused enhancements in the exonuclease activity in the presence of PCNA.

Polymerases:

Topics:

Status:

new topics/pols set partial results complete validated

Results:

No results available for this paper.

Entry validated by:

Log in to edit reference All References

Using Polbase tables:

Sorting:

Tables may be sorted by clicking on any of the column titles. A second click reverses the sort order. <Ctrl> + click on the column titles to sort by more than one column (e.g. family then name).

Filtering:

It is also possible to filter the table by typing into the search box above the table. This will instantly hide lines from the table that do not contain your search text.