DNA ligases catalyse the crucial step of joining the breaks in duplex DNA during DNA replication, repair and recombination, utilising either ATP or NAD(+) as a cofactor [1]. This family is a small zinc binding motif that is presumably DNA binding [1]. IT is found only in NAD dependent DNA ligases [1].

1: Crystal structure of NAD(+)-dependent DNA ligase: modular architecture and functional implications. Lee JY, Chang C, Song HK, Moon J, Yang JK, Kim HK, Kwon ST, Suh SW; EMBO J 2000;19:1119-1129. PMID:10698952