Molecular Dissection of the UvrC Protein Involved in Nucleotide Excision Repair in Listeria monocytogenes

Nucleotide excision repair (NER) is a conserved DNA repair pathway that removes a wide range of DNA lesions and preserves genome integrity. In bacteria, this process is carried out by the UvrABC excinuclease complex, in which UvrC performs dual incisions flanking the damaged sites. Despite its central role in repair, the biochemical properties and mechanistic features of UvrC from several pathogenic bacteria remain poorly defined. Here, we present a biochemical characterization of UvrC from Listeria monocytogenes (LmUvrC), a major food-borne pathogen. LmUvrC exhibits appreciable DNA-binding capability and DNA incision activity. Size-exclusion chromatography reveals that LmUvrC predominantly exists as a monomer in solution. In addition, the full-length LmUvrC harbours a cysteine-rich region capable of coordinating an iron-sulfur cluster, and deletion of this region leads to a complete loss of DNA-binding ability. Systematic deletion of additional domains demonstrates that efficient incision by LmUvrC requires coordinated contributions from both the GIY-YIG and RNase H domains, highlighting the importance of interdomain synergy and UvrB-mediated activation. Together, these findings establish a biochemical framework for UvrC, providing insights into NER in L. monocytogenes and revealing conserved mechanistic features of bacterial NER.