EC - RNA 3'-terminal-phosphate cyclase (ATP)

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IntEnz Enzyme Nomenclature


Accepted name:
RNA 3'-terminal-phosphate cyclase (ATP)
Other names:
RNA cyclase [ambiguous]
RNA-3'-phosphate cyclase [ambiguous]
rtcA (gene name)
Systematic name:
RNA-3'-phosphate:RNA ligase (cyclizing, AMP-forming)



The enzyme converts the 3'-terminal phosphate of various RNA substrates into the 2',3'-cyclic phosphodiester in an ATP-dependent reaction. Catalysis occurs by a three-step mechanism, starting with the activation of the enzyme by ATP, forming a phosphoramide bond between adenylate and a histidine residue [5,6]. The adenylate group is then transferred to the 3'-phosphate terminus of the substrate, forming the capped structure [RNA]-3'-(5'-diphosphoadenosine). Finally, the enzyme catalyses an attack of the vicinal O-2' on the 3'-phosphorus, which results in formation of cyclic phosphate and release of the adenylate. The enzyme also has a polynucleotide 5' adenylation activity [7]. cf. EC, RNA 3'-terminal-phosphate cyclase (GTP).

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ERGO , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC00989
Structural data: CSA , EC2PDB
Gene Ontology: GO:0003963
UniProtKB/Swiss-Prot: (90) [show] [UniProt]


  1. Filipowicz, W., Konarska, M., Gross, H.J. and Shatkin, A.J.
    RNA 3'-terminal phosphate cyclase activity and RNA ligation in HeLa cell extract.
    Nucleic Acids Res. 11: 1405-1418 (1983). [PMID: 6828385]
  2. Reinberg, D., Arenas, J. and Hurwitz, J.
    The enzymatic conversion of 3'-phosphate terminated RNA chains to 2',3'-cyclic phosphate derivatives.
    J. Biol. Chem. 260: 6088-6097 (1985). [PMID: 2581947]
  3. Genschik, P., Billy, E., Swianiewicz, M., Filipowicz, W.
    The human RNA 3'-terminal phosphate cyclase is a member of a new family of proteins conserved in Eucarya, Bacteria and Archaea.
    EMBO J. 16: 2955-2967 (1997). [PMID: 9184239]
  4. Genschik, P., Drabikowski, K., Filipowicz, W.
    Characterization of the Escherichia coli RNA 3'-terminal phosphate cyclase and its sigma54-regulated operon.
    J. Biol. Chem. 273: 25516-25526 (1998). [PMID: 9738023]
  5. Billy, E., Hess, D., Hofsteenge, J., Filipowicz, W.
    Characterization of the adenylation site in the RNA 3'-terminal phosphate cyclase from Escherichia coli.
    J. Biol. Chem. 274: 34955-34960 (1999). [PMID: 10574971]
  6. Tanaka, N., Shuman, S.
    Structure-activity relationships in human RNA 3'-phosphate cyclase.
    RNA 15: 1865-1874 (2009). [PMID: 19690099]
  7. Chakravarty, A. K., Shuman, S.
    RNA 3'-phosphate cyclase (RtcA) catalyzes ligase-like adenylylation of DNA and RNA 5'-monophosphate ends.
    J. Biol. Chem. 286: 4117-4122 (2011). [PMID: 21098490]
  8. Das, U., Shuman, S.
    2'-Phosphate cyclase activity of RtcA: a potential rationale for the operon organization of RtcA with an RNA repair ligase RtcB in Escherichia coli and other bacterial taxa.
    RNA 19: 1355-1362 (2013). [PMID: 23945037]

[EC created 1986, modified 1989, modified 2013, modified 2016]