LigD_Pol_like_3: Polymerase (Pol) domain of bacterial LigD proteins similar to Pseudomonas aeruginosa (Pae) LigD, subgroup 3. The LigD Pol domain belongs to the archaeal/eukaryal primase (AEP) superfamily. In prokaryotes, LigD along with Ku is required for non-homologous end joining (NHEJ)-mediated repair of DNA double-strand breaks (DSB). NHEJ-mediated DNA DSB repair is error-prone. It has been suggested that LigD Pol contributes to NHEJ-mediated repair DSB repair in vivo, by filling in short 5'-overhangs with ribonucleotides; the filled in termini would then be sealed by the associated LigD ligase domain, resulting in short stretches of RNA incorporated into the genomic DNA. The Pol domains of PaeLigD and Mycobacterium tuberculosis (Mt)LigD are stimulated by manganese, are error-prone, and prefer adding rNTPs to dNTPs in vitro; however PaeLigD and MtLigD belong to other subgroups, proteins in this subgroup await functional characterization.
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