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The binding of the exotoxin and antibody forms an antigen-antibody interaction and the exotoxins are targeted for destruction by the immune system. If this interaction does not happen, the exotoxins bind to the exotoxin receptors that are on the cell surface and causes death of the host cell by inhibiting protein synthesis. This figure also ...
The Pseudomonas exotoxin (or exotoxin A) is an exotoxin produced by Pseudomonas aeruginosa. [1] Vibrio cholerae produces a similar protein called the Cholix toxin 2] It inhibits elongation factor-2. It does so by ADP-ribosylation of EF2 using NAD+. This then causes the elongation of polypeptides to cease.
It is slightly unusual in that it combines the A and B parts in the same protein chain: the pre-toxin is cleaved into two parts, then the two parts are joined by a disulfide bond. [5] The exotoxin A of Pseudomonas aeruginosa is another example of an AB toxin that targets the eEF2. The "A" part is structually similar to the DT "A" part; the "B ...
Binding to the cell surface of the B subunit (the less stable of the two subunits) allows the A subunit (the more stable part of the protein) to penetrate the host cell. [4] The crystal structure of the diphtheria toxin homodimer has been determined to 2.5 Ångstrom resolution. The structure reveals a Y-shaped molecule consisting of three domains.
A complete AB5 toxin complex contains six protein units. Five units are similar or identical in structure and they comprise the B subunit. The last protein unit is unique and is known as the A subunit. General diagram of the A subunit of the AB5 toxin with the disulfide linkage. Ribbon diagram of the B-subunit of the cholera toxin.
Pertussis toxin is an exotoxin with six subunits (named S1 through S5—each complex contains two copies of S4). [12] [13] The subunits are arranged in A-B structure: the A component is enzymatically active and is formed from the S1 subunit, while the B component is the receptor-binding portion and is made up of subunits S2–S5. [13]
A new report by the Clean Label Project has found that protein powders may contain something other than muscle-building nutrients: lead and cadmium, both of which are toxic.. The national ...
SpeB was identified in 1919 as an ectoenzyme secreted by certain strains of streptococci. [11] It was originally studied as two separate toxins, streptococcal pyrogenic exotoxin B and streptococcal cysteine proteinase, until it was shown that both proteins were encoded by the speB gene and that the attributed pyrogenic activities were due to contamination by SpeA and SpeC.