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Information on EC 3.5.4.29 - GTP cyclohydrolase IIa and Organism(s) Methanocaldococcus jannaschii and UniProt Accession Q57609

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IUBMB Comments
Requires Mg2+. This enzyme catalyses the hydrolysis of the imidazole ring of guanosine 5'-triphosphate, N7-methylguanosine 5'-triphosphate or inosine 5'-triphosphate. Xanthosine 5'-triphosphate and ATP are not substrates. It also catalyses the hydrolysis of diphosphate to form two equivalents of phosphate. Unlike GTP cyclohydrolase II (EC 3.5.4.25), this enzyme does not release formate, but does hydrolyse the diphosphate from GTP to phosphate.
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Methanocaldococcus jannaschii
UNIPROT: Q57609
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The taxonomic range for the selected organisms is: Methanocaldococcus jannaschii
The enzyme appears in selected viruses and cellular organisms
Synonyms
gch iii, gtp cyclohydrolase iii, more
SYNONYM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
GTP cyclohydrolase III
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REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
GTP + 3 H2O = 2-amino-5-formylamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one + 2 phosphate
show the reaction diagram
although phosphate is the product of the enzymes phosphohydrolase activity, diphosphate is a likely intermediate
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
hydrolysis of diphosphate bonds
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-
-
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hydrolysis of phosphoric acid anhydridehydrolysis of C-N bond
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PATHWAY SOURCE
PATHWAYS
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SYSTEMATIC NAME
IUBMB Comments
GTP 8,9-hydrolase (phosphate-forming)
Requires Mg2+. This enzyme catalyses the hydrolysis of the imidazole ring of guanosine 5'-triphosphate, N7-methylguanosine 5'-triphosphate or inosine 5'-triphosphate. Xanthosine 5'-triphosphate and ATP are not substrates. It also catalyses the hydrolysis of diphosphate to form two equivalents of phosphate. Unlike GTP cyclohydrolase II (EC 3.5.4.25), this enzyme does not release formate, but does hydrolyse the diphosphate from GTP to phosphate.
CAS REGISTRY NUMBER
COMMENTARY hide
37289-19-3
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SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
beta,gamma-methylene-GTP + H2O
2-amino-5-formylamino-6-hydroxy-4-(5-phosphoribosylamino)-pyrimidine + methyl phosphonate
show the reaction diagram
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-
?
dGTP + H2O
2-amino-5-formylamino-6-hydroxy-4-(deoxy-5-phosphoribosylamino)-pyrimidine + phosphate
show the reaction diagram
-
-
?
diphosphate + H2O
2 phosphate
show the reaction diagram
-
-
?
GTP + 3 H2O
2-amino-5-formylamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one + 2 phosphate
show the reaction diagram
-
-
-
?
GTP + H2O
2-amino-5-formylamino-6-hydroxy-4-(5-phosphoribosylamino)-pyrimidine + phosphate
show the reaction diagram
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enzyme has diphosphate phosphohydrolase and GTP cyclohydrolase activities, no activity with 8-bromo-GTP, 8-azido-GTP, alpha,beta-methylene-GTP, ATP, GDP, GMP and XTP
?
GTP-gamma-S + H2O
2-amino-5-formylamino-6-hydroxy-4-(5-phosphoribosylamino)-pyrimidine + ?
show the reaction diagram
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-
?
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Ca2+
calcium is detected up to 10fold in molar excess of the protein. Treatment of the protein with Chelex (Na+ form) reduces the Ca2+ to 4fold excess but does not eliminate it
CoCl2
45% of Mg2+ diphosphate phosphohydrolase activation
Mn2+
7% of Mg2+ activation, 8% of Mg2+ diphosphate phosphohydrolase activation
Zn(OAc)2
21% of Mg2+ diphosphate phosphohydrolase activation
additional information
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
8-azido-GTP
0.6 mM, 91% inhibition of GTP cyclohydrolase activity, 0.3 mM, 53% inhibition of diphosphate phosphohydrolase activity
8-bromo-GTP
0.1 mM, 50% inhibition of GTP cyclohydrolase activity, 0.1 mM, 64% inhibition of diphosphate phosphohydrolase activity
alpha,beta-methylene-GTP
0.06 mM, 80% inhibition of GTP cyclohydrolase activity, 0.6 mM, 33% inhibition of diphosphate phosphohydrolase activity
beta,gamma-methylene-GTP
0.6 mM, 34% inhibition of GTP cyclohydrolase activity
diphosphate
inhibition of diphosphate phosphohydrolase activity at high concentrations
GDP
more than 40% inhibition of GTP cyclohydrolase activity
GMP
more than 40% inhibition of GTP cyclohydrolase activity
GTP-gamma-S
0.6 mM, 80% inhibition of GTP cyclohydrolase activity
IMP
0.6 mM, 25% inhibition of GTP cyclohydrolase activity
methylene diphosphate
0.6 mM, 40% inhibition of GTP cyclohydrolase activity, 0.6 mM, 56% inhibition of diphosphate phosphohydrolase activity
NaF
0.06 mM, 55% inhibition of diphosphate phosphohydrolase activity
phosphate
0.6 mM, 25% inhibition of GTP cyclohydrolase activity
tripolyphosphate
0.6 mM, 50% inhibition of GTP cyclohydrolase activity, 0.05 mM, 52% inhibition of diphosphate phosphohydrolase activity
XTP
0.6 mM, 52% inhibition of GTP cyclohydrolase activity
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
NH4+
activation of GTP cyclohydrolase activity, maximal activity at 50 mM
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.054 - 0.063
GTP
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.35 - 0.5
GTP
Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
0.39
recombinant enzyme
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
8 - 9
GTP hydrolase and diphosphate phosphohydrolase activity
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
70
GTP hydrolase and diphosphate phosphohydrolase activity
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
30275
3 * 30275, deduced from nucleotide sequence
30359
3 * 30359, MALDI-TOF mass spectrometry
37000
3 * 37000, SDS-PAGE
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
homotetramer
each monomer is composed of an N- and a C-terminal domain that adopt nearly superimposible structures, suggesting that the protein has arisen by gene duplication
trimer
CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
large square orthorhombic crystals containing the enzyme/GTP complex are obtained when both GTP and K+ is present in the crystallization drop and when Mg2+ is absent
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
H136Q
approx. 7 and 15% of wild-type GTP cyclohydrolase and diphosphate phosphohydrolase activity, respectively
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
4°C, 50 mM TAPS/KOH, pH 8.0, 150 mM KCl, 9 weeks, 20% loss of activity
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
heating, streptomycin, Mono Q, Sephacryl, recombinant enzyme
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
expression in Escherichia coli
overexpressed in Escheriochia coli
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Graham, D.E.; Xu, H.; White, R.H.
A member of a new class of GTP cyclohydrolases produces formylaminopyrimidine nucleotide monophosphates
Biochemistry
41
15074-15084
2002
Methanocaldococcus jannaschii (Q57609)
Manually annotated by BRENDA team
Morrison, S.D.; Roberts, S.A.; Zegeer, A.M.; Montfort, W.R., Bandarian, V.
A new use for a familiar fold: the X-ray crystal structure of GTP-bound GTP cyclohydrolase III from Methanocaldococcus jannaschii reveals a two metal ion catalytic mechanism
Biochemistry
47
230-242
2007
Methanocaldococcus jannaschii (Q57609), Methanocaldococcus jannaschii, Methanocaldococcus jannaschii DSM 2661 (Q57609)
Manually annotated by BRENDA team