J Biol Chem. 2003 Nov 7;278(45):43928-38 doi:10.1074/jbc.M307839200

Sawaya R, Schwer B, Shuman S.

Genetic and biochemical analysis of the functional domains of yeast tRNA ligase.

Trl1 can be separated in three funcionnal polypeptides : a cyclic phosphodiesterase, a A/GTP-dependant polynucleotide kinase, and an ATP-dependant 3′-hydroxyl,2′-phosphate – 5′-phosphate ligase.