FEATURES

DESCRIPTION

Also known as LIGD_MYCTU, ligD. With Ku forms a non-homologous end joining (NHEJ) repair enzyme which repairs DNA double-strand breaks (DSB) with reduced fidelity. Recognizes, processes and reseals DSBs, including repairs on incompatible DSB which require 3'-resection, gap filling and ligation. Anneals the 3' overhanging strands from opposing breaks to form a gapped intermediate, which then can be extended in trans by using the termini as primers for extension of the annealed break. Binds to the recessed 5'-phosphate moiety of the downstream DNA strand forming a stable synaptic complex even when the 3'-protruding ends of the template DNA strands are not complementary. Has numerous activities; gap filling copies the template strand, and prefers a 5'-phosphate in the gap and rNTPS (PubMed:17174332, PubMed:17947582), DNA-directed DNA or RNA polymerase on 5'-overhangs, terminal transferase (extending ssDNA or blunt dsDNA in a non-templated fashion, preferentially with rNTPs), DNA-dependent RNA primase (synthesizes short RNAs on unprimed closed ssDNA) and 3'- to 5'-exonuclease on ssDNA (PubMed:15499016). Isolated Pol domain (and presumably the holoenzyme) is able to form complexes between 2 noncompatible protruding 3'-ends DNA ends via microhomologous DNA strands, in a end-bridging function to which it adds a templated nucleotide (PubMed:17947582). Minimal primer length is 2 nucleotides (PubMed:21255731)., The preference of the polymerase domain for rNTPs over dNTPs may be advantageous in dormant cells, where the dNTP pool is limiting., In conjunction with endogenous or Mycobacterium phage Omega Ku (AC Q853W0) can reconstitute NHEJ in Saccharomyces cerevisiae. Monomer. Component of the NHEJ repair enzyme with mKu. Interacts with Ku in the absence of DSB via the Pol domain. In structures of the Pol domain with template DNA 2 Pol domains are bound to microhomologous DNA complexes to form an end-bridging complex. Probably interacts with Mycobacterium phage Omega and Corndog Ku homologs (AC Q853W0, AC Q856K7). Interacts with Sir2; may form a trimeric complex with LigD during NHEJ.

EXTERNAL LINKS

ligD

Mutations

Mutation(s) distribution

Mutations table