Properties and regulation of the GTPase activities of elongation factors Tu and G, and of initiation factor 2

  title={Properties and regulation of the GTPase activities of elongation factors Tu and G, and of initiation factor 2},
  author={Andrea Parmeggiani and Gernot Sander},
  journal={Molecular and Cellular Biochemistry},
SummaryDuring protein synthesis the interaction with ribosomes of elongation factors Tu (EF-Tu), G (EF-G) and initiation factor 2 (IF-2) is associated with the hydrolysis of GTP which is directly related to the functions of the factors. In this article we review systematically the properties of these GTPase activities in the presence and absence of protein synthesis, and by examining the characteristics of the different minimal systems for the expression of these activities we point to the role… 

Elongation Factor Tu Mutants and Site-Directed Mutagenesis of tufA

Besides intensifying the study of the presently available EF- Tu mutants selected with the help of kirromycin, a program aimed at modifying the tufA gene in positions that may code for single amino acids or segments of the polypeptide chain important for the different EF-Tu functions is started.

Interaction of Mycobacterium tuberculosis Elongation Factor Tu with GTP Is Regulated by Phosphorylation

The results show that the modulation of the MtbEf-Tu-GTP interaction by phosphorylation can have an impact on cellular protein synthesis and growth and suggest that the efficacy of an inhibitor can also depend on the posttranslational modification of the target and should be considered during the development of the molecule.

GTPases of the Translation Apparatus

The functional properties of translational GTPases as related to other G-proteins, the putative mechanism of GTP hydrolysis, structural features, and the functional cycles of translations are considered.

Bacterial elongation factors EF-Tu, their mutants, chimeric forms, and domains: isolation and purification.

  • J. Jonák
  • Biology
    Journal of chromatography. B, Analytical technologies in the biomedical and life sciences
  • 2007

Control of phosphate release from elongation factor G by ribosomal protein L7/12

Replacements of V66, I69, K70, and R73 in helix 4 increased the Michaelis constant (KM) of EF‐G·GTP for the ribosome, suggesting an involvement of these residues inEF‐G binding.

Effects of the mutation glycine-222----aspartic acid on the functions of elongation factor Tu.

The anomalous behavior of EF-TuBo is reflected in a remarkable increase of the fidelity in poly(Phe) synthesis, especially at high Mg2+ concentrations, as well as in the GTPase activity associated with the interaction of its ternary complex with the ribosome.

Activation of Elongation Factor G by Phosphate Analogues

It is shown that while EF-G•GDP does not stably bind to the ribosome and induce translocation, EFG• GDP in complex with phosphate group analogues BeF3 and AlF4 promotes the translocation of tRNA and mRNA.

EF-G Activation by Phosphate Analogs.



Energetic aspects of the EF-Tu-dependent GTPase activity. A study using the antibiotic kirromycin.

The Arrhenius plots derived from the GTPase activity of EF-Tu in the absence of kirromycin, and thus dependent upon the presence of aa-tRNA and mRNA · ribosomes, are much more complicated and at present are difficult to interpret.

Modification of elongation-factor-Tu . guanine-nucleotide interaction by kirromycin. A comparison with the effect of aminoacyl-tRNA and elongation factor Ts.

The results indicate that kirromycin induces a conformation of EF-Tu that shares features with the conformations evoked sequentially by EF-Ts, aminoacyl-tRNA and ribosomes during the elongation cycle, and the turnover activity occurring in the absence of the antibiotic and depending on aminoacyL-t RNA plus ribosome is limited by the dissociation rate of the EF- Tu · GDP complex.

Interaction of elongation factor Tu with the ribosome. A study using the antibiotic kirromycin.

Using this system, the following are found: (1) the 50S ribosomal subunit can substitute the 70S ribOSome; (2) the50S CsCl core a, b, and c particles can replace the 70s ribosome; and (3) addition of proteins L7/L12 with or without contaminating L10, did not induce any EF-Tu-dependent GTPase activity.

Effect of Kirromycin on Elongation Factor Tu

The results show that kirromycin's action appears to be directed towards a critical region of the EF-Tu molecule responsible for the regulation of the sites involved in the elongation process, and abolishing the requirement of GTP for formation of the aminoacyl-tRNA · EF- Tu complex.

Regulation of turnover GTPase activity of elongation factor G: the 30-S-coupled and 30-S-uncoupled reactions. Coordinated effects of cations, pH and polyamines.

Results suggest that the 30-S subunit may expose a critical region of the ribosomal RNA, leading to a greater affinity for EF-G, which may represent a vital function in suboptimal growth conditions, when cells are unable to maintain an even intracellular K+ concentration.