DNA ligase LigE increases bacterial transformation with damaged extracellular DNA

LigE is a periplasm‐targeted ATP‐dependent DNA ligase found in many Gram‐negative bacteria, including Neisseria gonorrhoeae . Although LigE has been shown to have a role in biofilm formation, many LigE‐possessing bacteria are also naturally competent, suggesting a possible role in transformation with extracellular DNA. Here, we demonstrate that LigE participates in competence by increasing transformation with nuclease‐damaged extracellular DNA that contains single‐stranded or cohesive breaks, and that this activity is dependent on its secretion signal peptide, indicating an extra‐cytoplasmic location of activity. We show that increased transformation with this restricted DNA is ATP‐dependent; however, the physiological source of ATP in the natural host remains unknown. Our findings highlight a potential role of Ngo‐LigE in Neisseria gonorrhoeae competence and horizontal gene transfer.