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

Nat Chem Biol. 2011 Nov 27;8(1):125-32. doi: 10.1038/nchembio.721.


The eukaryotic replicative DNA polymerases (Pol α, δ and ɛ) and the major DNA mutagenesis enzyme Pol ζ 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 δ 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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalytic Domain
  • DNA-Directed DNA Polymerase / chemistry
  • DNA-Directed DNA Polymerase / metabolism*
  • Iron / metabolism
  • Models, Molecular
  • Protein Binding
  • Protein Structure, Quaternary
  • Saccharomyces cerevisiae / enzymology*
  • Sulfur / metabolism


  • Sulfur
  • Iron
  • DNA-Directed DNA Polymerase