EC - CCA tRNA nucleotidyltransferase

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IntEnz Enzyme Nomenclature


Accepted name:
CCA tRNA nucleotidyltransferase
Other names:
CCA-adding enzyme, tRNA adenylyltransferase, tRNA cytidylyltransferase, tRNA CCA-pyrophosphorylase
transfer-RNA nucleotidyltransferase
transfer ribonucleic acid nucleotidyl transferase
CTP(ATP):tRNA nucleotidyltransferase
transfer ribonucleate adenylyltransferase
transfer ribonucleate adenyltransferase
transfer RNA adenylyltransferase
transfer ribonucleate nucleotidyltransferase
ATP(CTP):tRNA nucleotidyltransferase
ribonucleic cytidylic cytidylic adenylic pyrophosphorylase
transfer ribonucleic adenylyl (cytidylyl) transferase
transfer ribonucleic-terminal trinucleotide nucleotidyltransferase
transfer ribonucleate cytidylyltransferase
ribonucleic cytidylyltransferase
-C-C-A pyrophosphorylase
tRNA cytidylyltransferase
ATP(CTP)-tRNA nucleotidyltransferase
tRNA adenylyl(cytidylyl)transferase
CTP:tRNA cytidylyltransferase
tRNA CCA-diphosphorylase
CCA-adding enzyme
Systematic name:
CTP,CTP,ATP:tRNA cytidylyl,cytidylyl,adenylyltransferase



The acylation of all tRNAs with an amino acid occurs at the terminal ribose of a 3' CCA sequence. The CCA sequence is added to the tRNA precursor by stepwise nucleotide addition performed by a single enzyme that is ubiquitous in all living organisms. Although the enzyme has the option of releasing the product after each addition, it prefers to stay bound to the product and proceed with the next addition [5].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0052929 , GO:0052928 , GO:0052927
UniProtKB/Swiss-Prot: (362) [show] [UniProt]


  1. Schofield, P., Williams, K. R.
    Purification and some properties of Escherichia coli tRNA nucleotidyltransferase.
    J. Biol. Chem. 252: 5584-5588 (1977). [PMID: 328503]
  2. Shi, P. Y., Maizels, N., Weiner, A. M.
    CCA addition by tRNA nucleotidyltransferase: polymerization without translocation?
    EMBO J. 17: 3197-3206 (1998). [PMID: 9606201]
  3. Augustin, M. A., Reichert, A. S., Betat, H., Huber, R., Morl, M., Steegborn, C.
    Crystal structure of the human CCA-adding enzyme: insights into template-independent polymerization.
    J. Mol. Biol. 328: 985-994 (2003). [PMID: 12729736]
  4. Yakunin, A. F., Proudfoot, M., Kuznetsova, E., Savchenko, A., Brown, G., Arrowsmith, C. H., Edwards, A. M.
    The HD domain of the Escherichia coli tRNA nucleotidyltransferase has 2',3'-cyclic phosphodiesterase, 2'-nucleotidase, and phosphatase activities.
    J. Biol. Chem. 279: 36819-36827 (2004). [PMID: 15210699]
  5. Hou, Y. M.
    CCA addition to tRNA: implications for tRNA quality control.
    IUBMB Life 62: 251-260 (2010). [PMID: 20101632]

[EC created 2010]