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ENZYME entry: EC

Accepted Name
RNA 3'-terminal-phosphate cyclase (GTP)
Alternative Name(s)
RNA-3'-phosphate cyclase (GTP)
Reaction catalysed
a 3'-end 3'-phospho-ribonucleotide-RNA + GTP = a 3'-end 2',3'-cyclophospho-ribonucleotide-RNA + diphosphate + GMP
  • The enzyme, which is specific for GTP, was characterized from the archaeon Pyrococcus furiosus.
  • The enzyme converts the 3'-terminal phosphate of various RNA substrates into the 2',3'-cyclic phosphodiester in a GTP-dependent reaction.
  • Catalysis occurs by a three-step mechanism, starting with the activation of the enzyme by GTP, forming a phosphoramide bond between guanylate and a histidine residue.
  • The guanylate group is then transferred to the 3'-phosphate terminus of the substrate, forming the capped structure [RNA]- 3'-(5'-diphosphoguanosine).
  • Finally, the enzyme catalyzes an attack of the vicinal O-2' on the 3'-phosphorus, which results in formation of cyclic phosphate and release of the guanylate. cf. EC
PRIAM enzyme-specific profiles6.5.1.5
KEGG Ligand Database for Enzyme Nomenclature6.5.1.5
IUBMB Enzyme Nomenclature6.5.1.5
MEDLINEFind literature relating to
Rhea expert-curated reactions6.5.1.5

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