LigD is a multifunctional
ligase
In biochemistry, a ligase is an enzyme that can catalyze the joining ( ligation) of two molecules by forming a new chemical bond. This is typically via hydrolysis of a small pendant chemical group on one of the molecules, typically resulting i ...
/
polymerase
In biochemistry, a polymerase is an enzyme (Enzyme Commission number, EC 2.7.7.6/7/19/48/49) that synthesizes long chains of polymers or nucleic acids. DNA polymerase and RNA polymerase are used to assemble DNA and RNA molecules, respectively, by ...
/
nuclease
In biochemistry, a nuclease (also archaically known as nucleodepolymerase or polynucleotidase) is an enzyme capable of cleaving the phosphodiester bonds that link nucleotides together to form nucleic acids. Nucleases variously affect single and ...
(
3'-phosphoesterase) found in bacterial
non-homologous end joining
Non-homologous end joining (NHEJ) is a pathway that repairs double-strand breaks in DNA. It is called "non-homologous" because the break ends are directly ligated without the need for a homologous template, in contrast to homology directed repair ...
(NHEJ)
DNA repair
DNA repair is a collection of processes by which a cell (biology), cell identifies and corrects damage to the DNA molecules that encode its genome. A weakened capacity for DNA repair is a risk factor for the development of cancer. DNA is cons ...
systems.
It is much more error-prone than the more complex eukaryotic system of NHEJ, which uses multiple enzymes to fill its role.
The polymerase preferentially use rNTPs (RNA nucleotides), possibly advantageous in dormant cells.
The actual architecture of LigD is variable.
* The LigD homolog in ''
Bacillus subtilis
''Bacillus subtilis'' (), known also as the hay bacillus or grass bacillus, is a gram-positive, catalase-positive bacterium, found in soil and the gastrointestinal tract of ruminants, humans and marine sponges. As a member of the genus ''Bacill ...
'' does not have the nuclease domain.
* LigD with its ligase domain artificially removed can perform its function (with loss of fidelity) with a separate LigC acting as the ligase.
* The ''LigD'' homolog in the archaeon ''Methanocella paludicola'' is broken into three single-domain proteins sharing an operon.
References
{{reflist
DNA repair