What does elongation factor 2 do?
eEF2 (eukaryotic elongation factor 2) occupies an essential role in protein synthesis where it catalyses the translocation of the two tRNAs and the mRNA after peptidyl transfer on the 80 S ribosome.
What is ADP ribosylation of elongation factor 2?
Eukaryotic elongation factor 2 is the target of a class of bacterial mono-ADP-ribosyltransferase toxins which include the prototype, DT, exotoxin A from P. aeruginosa, and cholix toxin from V. cholera. Exposure of eukaryotic cells to these toxins leads to inhibition of protein synthesis and cell growth.
What factor is required for the expression of diphtheria toxin?
Two factors have great influence on the ability of Corynebacterium diphtheriae to produce the diphtheria toxin: (1) low extracellular concentrations of iron and (2) the presence of a lysogenic prophage in the bacterial chromosome.
How does diphtheria toxin stop protein synthesis?
Diphtheria Toxin (DT) Diphtheria toxin (DT) functions like other toxins by inhibiting protein synthesis either by modifying elongation factor-2 (EF2) or by acting directly on the ribosome (Siegall, 1994).
What is the function of elongation factor Ts in elongation?
Elongation Factor Ts Directly Facilitates the Formation and Disassembly of the Escherichia coli Elongation Factor Tu·GTP·Aminoacyl-tRNA Ternary Complex.
What is the role of EF-Tu?
Elongation factor thermal unstable Tu (EF-Tu) is a G protein that catalyzes the binding of aminoacyl-tRNA to the A-site of the ribosome inside living cells. Structural and biochemical studies have described the complex interactions needed to effect canonical function.
What type of toxin is diphtheria?
Diphtheria toxin is an exotoxin secreted by Corynebacterium, the pathogenic bacterium that causes diphtheria. The toxin gene is encoded by a prophage called corynephage β.
What is ADP ribosyl transferase?
ADP-ribosylation (ADPr) is a reversible post-translational modification of proteins, which controls major cellular and biological processes, including DNA damage repair, cell proliferation and differentiation, metabolism, stress and immune responses.
What is the function of the A subunit of the diphtheria toxin?
The A subunit of diphtheria toxin catalyzes ADP ribosylation of the elongation factor-2 (EF-2), inactivating it. The tox gene is encoded by a phage and is under the control of the repressor protein DtxR, which forms an iron complex, DtxR-Fe (Figure 2-11), that binds DNA and represses tox expression.
What is the most important virulence factor of Corynebacterium diphtheriae?
Toxins Diphtheria toxin
Toxins. Diphtheria toxin is the main virulence factor of C. diphtheriae and responsible for the life-threatening symptoms of respiratory diphtheria (Burkovski 2013b).
What do elongation factors do in translation?
Translation elongation factors are the workhorses of protein synthesis on the ribosome. They assist in elongating the nascent polypeptide chain by one amino acid at a time. The general biochemical outline of the translation elongation cycle is well preserved in all bio- logical kingdoms.
What do elongation factors do?