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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: P60785
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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 4
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ribosome-dependent GTPase
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translational GTPase
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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
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-
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?
additional information
?
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enzyme-ribosome binding analysis, overview. Binding of wild-type EF4 and mutant variants to the ribosome in the presence of guanine nucleotides, kinetics and affinities
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?
NATURAL SUBSTRATE
NATURAL 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
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
Thiostrepton
inhibits the stimulation of the enzyme's GTPase activity by the 70S ribosome
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
50S ribosome
stimulates the enzyme
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70S ribosome
required, stimulates the enzyme
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additional information
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KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.00032 - 0.27
GTP
additional information
additional information
Michaelis-Menten kinetics of GTP hydrolysis, stopped flow measurements, kinetic analysis of wild-type and mutant enzymes, overview
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TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.003 - 2.3
GTP
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.007 - 0.011
GTP
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
evolution
the translational GTPase LepA is a highly conserved bacterial protein
malfunction
metabolism
RsgA and LepA play partially redundant roles to ensure efficient 30S assembly
physiological function
LepA functions in ribosome biogenesis, analysis of the role of LepA in ribosome assembly, overview. LepA functions in biogenesis of the 30S subunit of the ribosome, rather than in translation elongation. The GTPase activity of LepA is stimulated by interactions with both subunits of the ribosome, implying that LepA acts at a late stage of assembly, in the context of the 70S ribosome
additional information
the last 44 C-terminal amino acids of elongation factor 4 form a subdomain within the C-terminal domain that is important for GTP-dependent function on the ribosome. Efficient nucleotide hydrolysis by the enzyme on the ribosome depends on its conserved residue His 81, which is essential for catalysis in EF4
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION?
LEPA_ECOLI
Escherichia coli (strain K12)
599
0
66570
Swiss-Prot
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PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
H81A
site-directed mutagenesis
additional information
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
recombinant His-tagged wild-type and mutant enzymes from Escherichia coli strain BL21(DE3) by nickel affinity chhrmatography and gel filtration
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
gene lepA, recombinant overexpression of His-tagged wild-type and mutant enzymes in Escherichia coli strain BL21(DE3)
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
De Laurentiis, E.I.; Wieden, H.J.
Identification of two structural elements important for ribosome-dependent GTPase activity of elongation factor 4 (EF4/LepA)
Sci. Rep.
5
8573
2015
Escherichia coli (P60785)
Manually annotated by BRENDA team
Gibbs, M.R.; Moon, K.M.; Chen, M.; Balakrishnan, R.; Foster, L.J.; Fredrick, K.
Conserved GTPase LepA (elongation factor 4) functions in biogenesis of the 30S subunit of the 70S ribosome
Proc. Natl. Acad. Sci. USA
114
980-985
2017
Escherichia coli (P60785)
Manually annotated by BRENDA team