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Literature summary for 3.6.5.3 extracted from

  • Fabbretti, A.; Brandi, L.; Milon, P.; Spurio, R.; Pon, C.L.; Gualerzi, C.O.
    Translation initiation without IF2-dependent GTP hydrolysis (2012), Nucleic Acids Res., 40, 7946-55.
    View publication on PubMedView publication on EuropePMC

Protein Variants

Protein Variants Comment Organism
E424K random mutagenesis, the IF2-G3 domain mutant shows a reduced affinity for the 30S ribosomal subunit, the mutant shows complete loss of GTPase activity Geobacillus stearothermophilus
E571K site-directed mutagenesis, the mutation in the 30S binding domain IF2-G3 disrupts hydrogen bonding between subdomains G2 and G3, so that IF2 acquires a GDP-like conformation and is no longer responsive to GTP binding. The mutant has a 6.5fold reduced affinity for the 30S subunit and is completely inactive in ribosome-dependent GTP hydrolysis. The IF2 E571K mutant is active in 30S initiation complex and initiation dipeptide formation, and supports faithful mRNA translation Escherichia coli
G420E random mutagenesis, the mutant shows a reduced affinity for both ribosomal subunits Geobacillus stearothermophilus
H301Y site-directed mutagenesis, GTPase-deficient mutant Geobacillus stearothermophilus
H448S site-directed mutagenesis, a dominant-lethal substitution, the expression of the mutant causes a rapid growth arrest and a reduction in the number of viable cells by 3 or 4 orders of magnitude within 20-30 min after induction Escherichia coli
H448S/E571K site-directed mutagenesis, induction of the GTPase-deficient double mutant affects neither the growth of the cells nor the viable counts demonstrating that the E571K mutation is capable of suppressing lethality of the dominant-lethal H448S substitution Escherichia coli
additional information GTPase null mutant E424K of Bacillus stearothermophilus can replace in vivo wild-type IF2 allowing the Escherichia coli infB null mutant to grow with almost wild-type duplication times Escherichia coli
additional information GTPase null mutant E424K of Bacillus stearothermophilus can replace in vivo wild-type IF2 allowing the Escherichia coli infB null mutant to grow with almost wild-type duplication times Geobacillus stearothermophilus
S387P random mutagenesis, the mutant shows a reduced affinity for the 30S ribosomal subunit Geobacillus stearothermophilus

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
additional information substrate binding kinetics of wild-type and mutant IF2s, overview Escherichia coli

Organism

Organism UniProt Comment Textmining
Escherichia coli
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gene infB
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Geobacillus stearothermophilus
-
-
-

Synonyms

Synonyms Comment Organism
IF2 GTPase
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Escherichia coli
IF2 GTPase
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Geobacillus stearothermophilus
translation initiation factor IF2
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Escherichia coli
translation initiation factor IF2
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Geobacillus stearothermophilus

General Information

General Information Comment Organism
additional information IF2 mutant E571K, modified in its 30S binding domain IF2-G3, can perform in vitro all individual translation initiation functions of wild-type IF2 and supports faithful messenger RNA translation, despite having a reduced affinity for the 30S subunit and being completely inactive in GTP hydrolysis Escherichia coli
physiological function importance of interdomain communication in IF2, importance of GTP as an IF2 ligand in the early initiation steps and the dispensability of the free energy generated by the IF2 GTPase in the late events of the translation initiation pathway Escherichia coli
physiological function importance of interdomain communication in IF2, importance of GTP as an IF2 ligand in the early initiation steps and the dispensability of the free energy generated by the IF2 GTPase in the late events of the translation initiation pathway Geobacillus stearothermophilus