The enzyme tRNA adenylyltransferase, also called tRNA-nucleotidyltransferase and CCA-adding enzyme, can add or repair the required CCA triplet at the 3'-end of tRNA molecules. Genes encoding tRNA include the CCA tail in some but not all bacteria, and this enzyme may be required for viability. Members of this family represent a distinct clade within the larger family pfam01743 (tRNA nucleotidyltransferase/poly(A) polymerase family protein). The example from Streptomyces coelicolor was shown to act as a CCA-adding enzyme and not as a poly(A) polymerase. [Protein synthesis, tRNA and rRNA base modification]
Jiyao W et al.(2023). "The conserved domain database in 2023.",