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Information on EC 3.6.5.3 - protein-synthesizing GTPase

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EC Tree
IUBMB Comments
This enzyme comprises a family of proteins involved in prokaryotic as well as eukaryotic protein synthesis. In the initiation factor complex, it is IF-2b (98 kDa) that binds GTP and subsequently hydrolyses it in prokaryotes. In eukaryotes, it is eIF-2 (150 kDa) that binds GTP. In the elongation phase, the GTP-hydrolysing proteins are the EF-Tu polypeptide of the prokaryotic transfer factor (43 kDa), the eukaryotic elongation factor EF-1alpha (53 kDa), the prokaryotic EF-G (77 kDa), the eukaryotic EF-2 (70-110 kDa) and the signal recognition particle that play a role in endoplasmic reticulum protein synthesis (325 kDa). EF-Tu and EF-1alpha catalyse binding of aminoacyl-tRNA to the ribosomal A-site, while EF-G and EF-2 catalyse the translocation of peptidyl-tRNA from the A-site to the P-site. GTPase activity is also involved in polypeptide release from the ribosome with the aid of the pRFs and eRFs.
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UNIPROT: Q980M3
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Word Map
The enzyme appears in viruses and cellular organisms
Synonyms
elongation factor, translation initiation factor, gtpase-activating protein, eif2alpha, eif2b, elongation factor tu, eef1a, ef-1alpha, eukaryotic initiation factor 2, elongation factor g, more
SYNONYM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
elongation factor (EF)
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GTP phosphohydrolase
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GTPase
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guanine triphosphatase
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guanosine 5'-triphosphatase
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guanosine triphosphatase
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initiation factor (IF)
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peptide-release or termination factor
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ribosomal GTPase
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REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
hydrolysis of phosphoric ester
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SYSTEMATIC NAME
IUBMB Comments
GTP phosphohydrolase (mRNA-translation-assisting)
This enzyme comprises a family of proteins involved in prokaryotic as well as eukaryotic protein synthesis. In the initiation factor complex, it is IF-2b (98 kDa) that binds GTP and subsequently hydrolyses it in prokaryotes. In eukaryotes, it is eIF-2 (150 kDa) that binds GTP. In the elongation phase, the GTP-hydrolysing proteins are the EF-Tu polypeptide of the prokaryotic transfer factor (43 kDa), the eukaryotic elongation factor EF-1alpha (53 kDa), the prokaryotic EF-G (77 kDa), the eukaryotic EF-2 (70-110 kDa) and the signal recognition particle that play a role in endoplasmic reticulum protein synthesis (325 kDa). EF-Tu and EF-1alpha catalyse binding of aminoacyl-tRNA to the ribosomal A-site, while EF-G and EF-2 catalyse the translocation of peptidyl-tRNA from the A-site to the P-site. GTPase activity is also involved in polypeptide release from the ribosome with the aid of the pRFs and eRFs.
CAS REGISTRY NUMBER
COMMENTARY hide
9059-32-9
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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
GTP + H2O
GDP + phosphate
show the reaction diagram
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Mg2+
requires Mg2+ for its full GTPase catalytic activity
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.0053 - 0.0141
GTP
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.0004 - 0.026
GTP
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.048 - 0.17
GTP
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION?
HFLX_SACS2
Saccharolobus solfataricus (strain ATCC 35092 / DSM 1617 / JCM 11322 / P2)
356
0
40538
Swiss-Prot
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SUBUNIT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
the enzyme binds to the 50S ribosomal subunit
CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
crystal structure of HflX from Sulfolobus solfataricus solved to 2.0 A resolution in apo- and GDP-bound forms
crystals of wild-type enzyme/GDP comple and mutant enzymes G235P and G235S are grown using hanging drop method at 16°C
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
F236P
kcat/Km is 63% compared to wild-type value
G235P
complete loss of GTP hydrolyzing activity
G235S
partial loss of GTP hydrolyzing activity
N189P
complete loss of GTP hydrolyzing activity
T193N
complete loss of GTP hydrolyzing activity
T213V
kcat is 45% compared to the wild-type value
additional information
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
expression in Escherichia coli
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Blombach, F.; Launay, H.; Zorraquino, V.; Swarts, D.C.; Cabrita, L.D.; Benelli, D.; Christodoulou, J.; Londei, P.; van der Oost, J.
An HflX-type GTPase from Sulfolobus solfataricus binds to the 50S ribosomal subunit in all nucleotide-bound states
J. Bacteriol.
193
2861-2867
2011
Saccharolobus solfataricus (Q980M3), Saccharolobus solfataricus P2 (Q980M3)
Manually annotated by BRENDA team
Huang, B.; Wu, H.; Hao, N.; Blombach, F.; van der Oost, J.; Li, X.; Zhang, X.C.; Rao, Z.
Functional study on GTP hydrolysis by the GTP-binding protein from Sulfolobus solfataricus, a member of the HflX family
J. Biochem.
148
103-113
2010
Saccharolobus solfataricus (Q980M3), Saccharolobus solfataricus, Saccharolobus solfataricus P2 (Q980M3)
Manually annotated by BRENDA team
Wu, H.; Sun, L.; Blombach, F.; Brouns, S.J.; Snijders, A.P.; Lorenzen, K.; van den Heuvel, R.H.; Heck, A.J.; Fu, S.; Li, X.; Zhang, X.C.; Rao, Z.; van der Oost, J.
Structure of the ribosome associating GTPase HflX.
Proteins
78
705-713
2010
Saccharolobus solfataricus (Q980M3), Saccharolobus solfataricus, Saccharolobus solfataricus P2 (Q980M3)
Manually annotated by BRENDA team