Table of Contents
What do ADP Ribosylating toxins do?
Each bacterial ADP-ribosyltransferase toxin modifies a specific host protein(s) that yields a unique pathology. These toxins possess the capacity to enter a host cell or to use a bacterial Type III apparatus for delivery into the host cell.
What is the receptor for diphtheria toxin?
Iwamoto, R. et al. Heparin-binding EGF-like growth factor, which acts as the diphtheria toxin receptor, forms a complex with membrane protein DRAP27/CD9, which up-regulates functional receptors and diphtheria toxin sensitivity.
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 ADP-ribosylation of G protein?
Mono-ADP-ribosylation is a post-translational modification that is catalyzed by bacterial toxins and eukaryotic enzymes and consists of the transfer of the ADP-ribose moiety from β-NAD+ to a specific amino acid of various cellular proteins (1,–3).
What type of toxin is diphtheria toxin?
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. The toxin causes the disease in humans by gaining entry into the cell cytoplasm and inhibiting protein synthesis.
What type of toxin is pertussis toxin?
Pertussis toxin is a secreted protein exotoxin and an important virulence factor produced exclusively by B. pertussis. PT is transported across the bacterial outer membrane by a type IV secretion system encoded by the ptl genes, which are located downstream from the ptx genes encoding the toxin [7,8].
How does pertussis toxin affect G protein?
Pertussis toxin is isolated from the bacteria Bordetella pertussis. It is shown to modify the function of G proteins by catalyzing the ADP-ribosylation of a cysteine residue on the carboxy terminal of α subunit of Gi and Go.
How is diphtheria toxin formed?
Diphtheria toxin is synthesized by toxigenic strains of Corynebacterium diphtheriae in precursor form and following cleavage of its 25 amino acid signal sequence, it is released into the culture medium as a 535 amino acid single chain protein [2,3,4].
Is pertussis toxin an endotoxin?
pertussis, as a Gram-negative bacterium, harbours naturally lipopolysaccharide (LPS, also known as endotoxin), one of the strongest stimulators of monocytes.