MtLigD_Pol_like: Polymerase (Pol) domain of bacterial LigD proteins similar to Mycobacterium tuberculosis (Mt)LigD. 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. MtLigD is monomeric and contains an N-terminal Pol domain, a central phosphoesterase module, and a C-terminal ligase domain. It has been suggested that LigD Pol contributes to NHEJ-mediated DNA 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 MtLigD Pol domain is stimulated by manganese, is error-prone, and prefers adding rNTPs to dNTPs in vitro. The MtLigD Pol domain has been shown to prefer DNA gapped substrates containing a 5'-phosphate group at the gap.
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