DNA ligase D <p>Members of this entry are DNA ligases involved in the repair of DNA double-stranded breaks by non-homologous end joining (NheJ). The system of the bacterial Ku protein (<db_xref db="INTERPRO" dbkey="IPR009187"/>) plus this DNA ligase is seen in about 20% of bacterial genomes to date and at least one archaeon (Archeoglobus fulgidus). This entry describes a central and C-terminal domain. These two domains may be permuted, as in genus Mycobacterium, or divided into tandem ORFs. An additional N-terminal 3 -phosphoesterase (PE) domain (<db_xref db="INTERPRO" dbkey="IPR014144"/>) is present in some members of this ligase. Most examples of genes for this ligase are adjacent to the gene for Ku.</p>