Structural and functional investigation of DinG containing a 3′–5′ exonuclease domain

DNA helicases and exonucleases play essential roles in genome maintenance; however, little is known about bacterial helicase-exonuclease fusion proteins. This study examines DNA helicases and exonucleases that play essential roles in genome maintenance; however, little is known about bacterial helicase-exonuclease fusion proteins. This study provides the first structural and functional characterization of <i>Staphylococcus aureus</i> DinG (SaDinG), a unique enzyme that combines 5'-3' helicase and 3'-5' exonuclease activities. Our findings resolve previous uncertainties about SaDinG's function and reveal an ATP-dependent regulatory mechanism that modulates its activity. Additionally, we demonstrate that SaDinG is critical for bacterial resistance to DNA crosslinking agents. These insights not only expand our understanding of bacterial DNA repair but also suggest potential avenues for targeting DinG-like enzymes in antimicrobial strategies. Given the growing concerns over antibiotic resistance, understanding how bacteria maintain genome integrity under stress conditions is crucial. This work lays the foundation for further exploration of bacterial helicase-exonuclease systems and their role in genome stability and adaptive survival.