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Entry
EC 6.5.1.5                  Enzyme                                 

Name
RNA 3'-terminal-phosphate cyclase (GTP);
Pf-Rtc;
RNA-3'-phosphate cyclase (GTP)
Class
Ligases;
Forming phosphoric-ester bonds;
Ligases that form phosphoric-ester bonds (only sub-subclass identified to date)
BRITE hierarchy
Sysname
RNA-3'-phosphate:RNA ligase (cyclizing, GMP-forming)
Reaction(IUBMB)
GTP + [RNA]-3'-(3'-phospho-ribonucleoside) = GMP + diphosphate + [RNA]-3'-(2',3'-cyclophospho)-ribonucleoside (overall reaction) [RN:R10537];
(1a) GTP + [RNA 3'-phosphate cyclase]-L-histidine = 5'-guanosyl [RNA 3'-phosphate cyclase]-Ntau-phosphono-L-histidine + diphosphate;
(1b) 5'-guanosyl [RNA 3'-phosphate cyclase]-Ntau-phosphono-L-histidine + [RNA]-3'-(3'-phospho-ribonucleoside) = [RNA 3'-phosphate cyclase]-L-histidine + [RNA]-3'-ribonucleoside-3'-(5'-diphosphoguanosine);
(1c) [RNA]-3'-ribonucleoside-3'-(5'-diphosphoguanosine) = [RNA]-3'-(2',3'-cyclophospho)-ribonucleoside + GMP
Reaction(KEGG)
Substrate
GTP [CPD:C00044];
[RNA]-3'-(3'-phospho-ribonucleoside);
[RNA 3'-phosphate cyclase]-L-histidine;
5'-guanosyl [RNA 3'-phosphate cyclase]-Ntau-phosphono-L-histidine;
[RNA]-3'-ribonucleoside-3'-(5'-diphosphoguanosine)
Product
GMP [CPD:C00144];
diphosphate [CPD:C00013];
[RNA]-3'-(2',3'-cyclophospho)-ribonucleoside;
5'-guanosyl [RNA 3'-phosphate cyclase]-Ntau-phosphono-L-histidine;
[RNA 3'-phosphate cyclase]-L-histidine;
[RNA]-3'-ribonucleoside-3'-(5'-diphosphoguanosine)
Comment
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 catalyses 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 6.5.1.4, RNA-3'-phosphate cyclase (ATP).
History
EC 6.5.1.5 created 2013, modified 2016
Orthology
K18105  
RNA 3'-terminal phosphate cyclase (GTP)
Genes
MKA: 
MK0001(rcl1)
PHO: 
PH1529(PH1529)
PAB: 
PFU: 
PFI: 
PYN: 
PYA: 
PYS: 
TKO: 
TON: 
TGA: 
TGAM_2020(rtcA)
TSI: 
TBA: 
THE: 
THA: 
THM: 
TLT: 
 » show all
Taxonomy
Reference
1  [PMID:22074260]
  Authors
Sato A, Soga T, Igarashi K, Takesue K, Tomita M, Kanai A
  Title
GTP-dependent RNA 3'-terminal phosphate cyclase from the hyperthermophilic archaeon Pyrococcus furiosus.
  Journal
Genes. Cells. 16 (2011) 1190-9.
  Sequence
[pfu:PF1549]
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 

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