tRNA nucleotidyltransferase involved in the synthesis of the tRNA CCA terminus. Adds the terminal adenosine residue to tRNA (PubMed:11701927, PubMed:25914059). Can incorporate CMP into tRNA ending with C74C75 (tRNACC), with very weak efficiency (PubMed:25914059). a tRNA with a 3' CC end + ATP = a tRNA with a 3' CCA end + diphosphate kcat is 0.10 min(-1) for incorporation of AMP into tRNACC. kcat is 0.00015 min(-1) for incorporation of CMP into tRNACC. Adopts a seahorse-like shape and consists of four domains: head, neck, body, and tail. Belongs to the tRNA nucleotidyltransferase/poly(A) polymerase family.