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Literature summary for 3.6.5.3 extracted from

  • Koripella, R.K.; Holm, M.; Dourado, D.; Mandava, C.S.; Flores, S.; Sanyal, S.
    A conserved histidine in switch-II of EF-G moderates release of inorganic phosphate (2015), Sci. Rep., 5, 12970 .
    View publication on PubMedView publication on EuropePMC

Activating Compound

Activating Compound Comment Organism Structure
additional information GTP hydrolysis by EF-G gets strongly stimulated by the ribosome Escherichia coli

Protein Variants

Protein Variants Comment Organism
F94L site-directed mutagenesis, the mutant shows GTP hydrolysis kinetics similar to the wild-type Escherichia coli
H91A site-directed mutagenesis, the mutant shows defective ribosome associated GTP hydrolysis and inorganic phosphate release Escherichia coli
H91E site-directed mutagenesis, the mutant shows defective ribosome associated GTP hydrolysis and inorganic phosphate release Escherichia coli
H91Q site-directed mutagenesis, the mutant is defective in inorganic phosphate release Escherichia coli
H91R site-directed mutagenesis, the mutant shows defective ribosome associated GTP hydrolysis and inorganic phosphate release Escherichia coli
additional information intrinsic GTP hydrolysis by EF-G is unaffected by the H91 and F94 mutations. H91 mutated EF-Gs show different degrees of defect in ribosome-stimulated GTP hydrolysis. H91 mutants show larger defects in Pi release than in GTP hydrolysis Escherichia coli

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.0081
-
GTP in presence of 70S ribosome, H91E, pH 7.5, 37°C Escherichia coli
0.0082
-
GTP in presence of 70S ribosome, wild-type enzyme, pH 7.5, 37°C Escherichia coli
0.0085
-
GTP in presence of 70S ribosome, F94L, pH 7.5, 37°C Escherichia coli
0.0106
-
GTP in presence of 70S ribosome, H91A, pH 7.5, 37°C Escherichia coli
0.0134
-
GTP in presence of 70S ribosome, H91Q, pH 7.5, 37°C Escherichia coli
0.0143
-
GTP in presence of 70S ribosome, H91R, pH 7.5, 37°C Escherichia coli

Localization

Localization Comment Organism GeneOntology No. Textmining
ribosome
-
Escherichia coli 5840
-

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ required for catalysis Escherichia coli

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
GTP + H2O Escherichia coli
-
GDP + phosphate
-
?

Organism

Organism UniProt Comment Textmining
Escherichia coli P0A6M8
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
GTP + H2O
-
Escherichia coli GDP + phosphate
-
?

Synonyms

Synonyms Comment Organism
EF-G
-
Escherichia coli
elongation factor G
-
Escherichia coli
translational GTPase
-
Escherichia coli

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
37
-
assay at Escherichia coli

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
1.9
-
GTP in presence of 70S ribosome, H91E, pH 7.5, 37°C Escherichia coli
2 8 GTP in presence of 70S ribosome, H91A, pH 7.5, 37°C Escherichia coli
27
-
GTP in presence of 70S ribosome, H91R, pH 7.5, 37°C Escherichia coli
170
-
GTP in presence of 70S ribosome, F94L, pH 7.5, 37°C Escherichia coli
174
-
GTP in presence of 70S ribosome, H91Q, pH 7.5, 37°C Escherichia coli
202
-
GTP in presence of 70S ribosome, wild-type enzyme, pH 7.5, 37°C Escherichia coli

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.5
-
assay at Escherichia coli

General Information

General Information Comment Organism
evolution elongation factor G (EF-G) belongs to the subfamily of translational G-proteins in the GTPase superfamily. All G-proteins share a nucleotide binding G domain, which contains distinct and highly conserved elements (G1-G5). The G3 sequence motif, switch II, is highly flexible and contains a DXXG sequence Escherichia coli
malfunction intrinsic GTP hydrolysis by EF-G is unaffected by the H91 and F94 mutations. H91 mutated EF-Gs show different degrees of defect in ribosome-stimulated GTP hydrolysis. H91 mutants show larger defects in Pi release than in GTP hydrolysis Escherichia coli
additional information a conserved histidine in switch-II of EF-G moderates release of inorganic phosphate. EF-G possesses a conserved histidine 91 at the apex of switch-II, which is implicated in GTPase activation and GTP hydrolysis, H91 facilitates phosphate release. In crystal structures of the ribosome bound EF-G-GTP a tight coupling between H91 and the gamma-phosphate of GTP can be seen. Following GTP hydrolysis, H91 flips about 140° in the opposite direction, probably with phosphate still coupled to it, promoting phosphate to detach from GDP and reach the inter-domain space of EF-G, which constitutes an exit path for the phosphate, molecular dynamics simulations, overview. Mg2+ ion plays a vital role in the process Escherichia coli
physiological function elongation factor G (EF-G) is a translational GTPase responsible for tRNA-mRNA translocation Escherichia coli