DNA-Mediated Redox Signaling in Bacterial Nucleotide Excision Repair by UvrC

Abstract

Our laboratory has proposed redox signaling among DNA repair proteins containing 4Fe-4S clusters through DNA charge transport (DNA CT) as a first step in lesion detection. Recently, we have explored whether UvrC, the endonuclease in Nucleotide Excision Repair (NER), may also contain a 4Fe-4S cluster. A new purification route was developed to express an MBP-UvrC fusion protein, and evidence of a 4Fe-4S cluster was seen by UV-Visible (UV-Vis) and Electron Paramagnetic Resonance (EPR) spectroscopy. Like other 4Fe-4S repair proteins studied in our lab, MBP-UvrC can participate in DNA CT chemistry, as evidenced by its electrochemical activity on DNA-modified gold electrodes. Complementing in vivo genetic assays have been developed and indicate that DNA-mediated signaling between UvrC and other DNA-processing enzymes containing 4Fe-4S clusters is occurring. Taken together, these results have suggested that UvrC is part of a network of 4Fe-4S proteins that communicate using DNA CT to find lesions and maintain genomic integrity. Additional in vitro and in vivo characterization is underway to understand further the biological implications of the newly-discovered, DNA-mediated redox chemistry of UvrC.

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