This domain is found in two copies toward the C-terminal end of human Isoleucine--tRNA ligase, cytoplasmic (IARS1) and similar sequences predominantly found in vertebrates. IARS1 catalyses the specific attachment of an amino acid to its cognate tRNA in a 2 step reaction: the amino acid (AA) is first activated by ATP to form AA-AMP and then transferred to the acceptor end of the tRNA. This domain is predicted to adopt an ubiquitin-like fold.
