LigD polymerase domain, PaeLigD-type (IPR033651)

Short name: PaeLigD_Pol-like

Overlapping homologous superfamilies


Domain relationships


This entry represents the polymerase (Pol) domain of bacterial LigD proteins similar to Pseudomonas aeruginosa (Pae) 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. PaeLigD is monomeric, containing an N-terminal phosphoesterase module, a central polymerase (Pol) domain, and a C-terminal ATP-dependent 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 PaeLigD Pol domain in vitro, in a manganese-dependent fashion, catalyzes templated extensions of 5'-overhang duplex DNA, and nontemplated single-nucleotide additions to blunt-end duplex DNA; it preferentially adds single ribonucleotides at blunt DNA ends. PaeLigD Pol adds a correctly paired rNTP to the DNA primer termini more rapidly than it does a correctly paired dNTP; it has higher infidelity as an RNA polymerase than it does as a DNA polymerase, which is in keeping with the mutagenic property of NHEJ-mediated DNA DSB repair [PMID: 16446439, PMID: 16816388, PMID: 15520014, PMID: 15897197, PMID: 16027112, PMID: 11075926].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.