A Redox Role for the [4Fe4S] Cluster of Yeast DNA Polymerase δ
A [4Fe4S]^(2+) cluster in the C-terminal domain of the catalytic subunit of the eukaryotic B-family DNA polymerases is essential for the formation of active multi-subunit complexes. Here we use a combination of electrochemical and biochemical methods to assess the redox activity of the [4Fe4S]^(2+) cluster in Saccharomyces cerevisiae polymerase (Pol) δ, the lagging strand DNA polymerase. We find that Pol δ bound to DNA is indeed redox-active at physiological potentials, generating a DNA-mediated signal electrochemically with a midpoint potential of 113 ± 5 mV versus NHE. Moreover, biochemical assays following electrochemical oxidation of Pol δ reveal a significant slowing of DNA synthesis that can be fully reversed by reduction of the oxidized form. A similar result is apparent with photooxidation using a DNA-tethered anthraquinone. These results demonstrate that the [4Fe4S] cluster in Pol δ can act as a redox switch for activity, and we propose that this switch can provide a rapid and reversible way to respond to replication stress.
© 2017 American Chemical Society. Received: September 26, 2017; Published: November 22, 2017. We are grateful to the NIH (GM120087 to J.K.B., GM118129 to P.M.B.) and US-Israel Binational Science Foundation (2013358 to P.M.B.) for their financial support of this work. The authors declare no competing financial interest.
Accepted Version - nihms953167.pdf
Supplemental Material - ja7b10284_si_001.pdf