Members of this family include T4 phage proteins with ATP-dependent RNA ligase activity. Host defence to phage may include cleavage and inactivation of specific tRNA molecules; members of this family act to reverse this RNA damage. The enzyme is adenylated, transiently, on a Lys residue in a motif KXDGSL. This family also includes fungal tRNA ligases that have adenylyltransferase activity [1]. tRNA ligases are enzymes required for the splicing of precursor tRNA molecules containing introns.i

1: Genetic and biochemical analysis of the functional domains of yeast tRNA ligase. Sawaya R, Schwer B, Shuman S; J Biol Chem 2003;278:43928-43938. PMID:12933796