| Type: | Family | Name: | Binary exotoxin A, clostridial type |
| Description: | A large group of bacterial exotoxins are referred to as "A/B toxins", essentially because they are formed from two subunits. The "A" subunitpossesses enzyme activity, and is transferred to the host cell following a conformational change in the membrane-bound transport "B" subunit [].Clostridial species are one of the major causes of food poisoning/gastro- intestinal illnesses. They are Gram-positive, spore-forming rods that occurnaturally in the soil []. Included in the family are: Clostridium botulinum, which produces one of the most potent toxins in existence; Clostridium tetani, causative agent of tetanus; and Clostridium perfringens, commonly found in wound infections and diarrhoea cases. Among the toxins produced by certain Clostridium spp. are the binary exotoxins. These proteins consist of two independent polypeptides, whichcorrespond to the A/B subunit moieties. The enzyme component (A) enters the cell through endosomes produced by the oligomeric binding/translocationprotein (B), and prevents actin polymerisation through ADP-ribosylation of monomeric G-actin [, , ].Members of the "A" binary toxin family include C. perfringens iota toxin Ia [], C. botulinum C2 toxin CI [], and Clostridium difficileADP-ribosyltransferase []. Other homologous proteins have been found in Clostridium spiroforme[, ], and related bacteria such as Bacillus species. | Short Name: | Binary_toxinA_clost-typ |
