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 is ADP ribosylation catalyzed by diphtheria toxin?
A major subset of such toxins is the NAD(+)-dependent ADP-ribosylating exotoxins, which include pertussis, cholera, and diphtheria toxin. Diphtheria toxin catalyzes the ADP ribosylation of the diphthamide residue of eukaryotic elongation factor 2 (eEF-2).
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.
Which of the following enzymes catalyze the ADP-ribosylation of key cellular enzymes or proteins?
5. Which of the following enzymes catalyze the ADP-ribosylation of key cellular enzymes or proteins? Explanation: The enzymes that catalyse the ADP-ribosylation and inactivation of key cellular enzymes or proteins are diphteria toxin and cholera toxin.
What type of toxin is diphtheria?
Diphtheria toxin belongs to the so-called bifunctional A–B toxins (Figure 2-10). Portion A mediates the enzymatic activity responsible for halting protein synthesis in the target cell while portion B binds to a cell receptor and mediates the translocation of the A chain into the cytosol.
What is the mechanism of action of diphtheria toxin?
Diphtheria toxin kills cells by inhibiting eukaryotic protein synthesis, and its mechanism of action has been extensively characterized. This potent toxin inactivates elongation factor (EF-2) required for protein synthesis (Collier, 1967).
What is the meaning of Ribosylation?
Noun. ribosylation (plural ribosylations) (biochemistry) The attachment of a ribose or ribosyl group to a molecule, especially to a polypeptide or protein.
Is ADP a Ribosylation?
ADP-ribosylation is the addition of one or more ADP-ribose moieties to a protein. It is a reversible post-translational modification that is involved in many cellular processes, including cell signaling, DNA repair, gene regulation and apoptosis. Improper ADP-ribosylation has been implicated in some forms of cancer.
Which of the following takes place due to phosphorylation of isocitrate dehydrogenase?
Which of the following takes place due to phosphorylation of isocitrate dehydrogenase? Explanation: The electrostatic repulsion by the phosphoryl group inhibits the binding of citrate at active site. 10.
What is ADP ribosylation?
ADP ribose. ADP-ribosylation is the addition of one or more ADP-ribose moieties to a protein. It is a reversible post-translational modification that is involved in many cellular processes, including cell signaling, DNA repair, gene regulation and apoptosis.
How does ADP-ribosylation affect translation elongation factor 2 (eEF2)?
Eukaryotic translation elongation factor 2 (eEF2) facilitates the movement of the peptidyl tRNA-mRNA complex from the A site of the ribosome to the P site during protein synthesis. ADP-ribosylation (ADP (R)) of eEF2 by bacterial toxins on a unique diphthamide residue inhibits its translocation activity, but the mechanism is unclear.
How does mono ADP ribosylation work?
Mono ADP-ribosylation Mono-ADP ribosyltransferases commonly catalyze the addition of ADP-ribose to arginine side chains using a highly conserved R-S-EXE motif of the enzyme. The reaction proceeds by breaking the bond between nicotinamide and ribose to form an oxonium ion.
What is the role of poly (ADP-ribose) polymerase 2 (PARP-2)?
^ Schreiber, V; Amé, JC; Dollé, P; Schultz, I; Rinaldi, B; Fraulob, V; Ménissier-de Murcia, J; de Murcia, G (June 21, 2002). “Poly (ADP-ribose) polymerase-2 (PARP-2) is required for efficient base excision DNA repair in association with PARP-1 and XRCC1”.