Calcium is a cofactor of polymerization but inhibits pyrophosphorolysis by the Sulfolobus solfataricus DNA polymerase Dpo4.

@article{Irimia2006CalciumIA,
  title={Calcium is a cofactor of polymerization but inhibits pyrophosphorolysis by the Sulfolobus solfataricus DNA polymerase Dpo4.},
  author={Adriana Irimia and Hong Zang and Lioudmila V. Loukachevitch and Robert L. Eoff and F Peter Guengerich and Martin Egli},
  journal={Biochemistry},
  year={2006},
  volume={45 19},
  pages={5949-56}
}
Y-Family DNA polymerase IV (Dpo4) from Sulfolobus solfataricus serves as a model system for eukaryotic translesion polymerases, and three-dimensional structures of its complexes with native and adducted DNA have been analyzed in considerable detail. Dpo4 lacks a proofreading exonuclease activity common in replicative polymerases but uses pyrophosphorolysis to reduce the likelihood of incorporation of an incorrect base. Mg(2+) is a cofactor for both the polymerase and pyrophosphorolysis… CONTINUE READING