Eukaryotic DNA polymerases require an iron-sulfur cluster for the formation of active complexes.

ABSTRACT: The eukaryotic replicative DNA polymerases (Pol ?, ? and ?) and the major DNA mutagenesis enzyme Pol ? contain two conserved cysteine-rich metal-binding motifs (CysA and CysB) in the C-terminal domain (CTD) of their catalytic subunits. Here we demonstrate by in vivo and in vitro approaches the presence of an essential [4Fe-4S] cluster in the CysB motif of all four yeast B-family DNA polymerases. Loss of the [4Fe-4S] cofactor by cysteine ligand mutagenesis in Pol3 destabilized the CTD and abrogated interaction with the Pol31 and Pol32 subunits. Reciprocally, overexpression of accessory subunits increased the amount of the CTD-bound Fe-S cluster. This implies an important physiological role of the Fe-S cluster in polymerase complex stabilization. Further, we demonstrate that the Zn-binding CysA motif is required for PCNA-mediated Pol ? processivity. Together, our findings show that the function of eukaryotic replicative DNA polymerases crucially depends on different metallocenters for accessory subunit recruitment and replisome stability.

SUBMITTER: Netz DJ 

PROVIDER: S-EPMC3241888 | biostudies-literature | 2011 Nov

REPOSITORIES: biostudies-literature