Fig. 5

Mechanism of ligD mediated nick ligation in B. subtilis. a The ligD-mediated nick re-ligation. A Ku homodimer binds to the end of the DNA break and recruits LigD protein. The polymerase domain of LigD specifically binds to a 5′-phosphate (P) and promotes end-synapsis-, together with protein Ku. The nuclease and polymerase activities of LigD, and possibly other factors, process the break termini, if required, to restore complementary ends. Finally, ligation of the nick by LigD repairs the break. b Predominantly HDR repair in ΔligD. When LigD is repressed, the DNA break is repaired by the HDR mechanism