Physical changes in the epsilon prototoxin molecule of Clostridium perfringens during enzymatic activation

Abstract

Enzymatic activation of Clostridium perfringens epsilon prototoxin removed a small basic part of the molecule, causing a slight change in molecular weight (32,700 to 31,200) and a large change in isoelectric point (from pH 8.02 into fractions of 5.36 and 5.74).

Cloning and nucleotide sequencing of the Clostridium perfringens epsilon-toxin gene and its expression in Escherichia coli

“…The molecular weight of mature epsilon-prototoxin calculated from the derived amino acid sequence (32,981) agreed with our experimentally determined value for the cloned and native proteins of 33,000. Previously, a range of molecular weights for the protein have been reported (from 23,200 to 40,500 [22]), although more recent estimates (29,45) are much closer to our value. The isoelectric points of epsilon-prototoxin and epsilontoxin have been reported to be 8.02 and 5.36, respectively (45).…”

“…Previously, a range of molecular weights for the protein have been reported (from 23,200 to 40,500 [22]), although more recent estimates (29,45) are much closer to our value. The isoelectric points of epsilon-prototoxin and epsilontoxin have been reported to be 8.02 and 5.36, respectively (45). The estimated pIs of cloned prototoxin (8.35) and toxin (5.4) differ slightly from those of the previous reports but are identical to the major pIs of the purified proteins from C. perfringens type D, which we have determined.…”

“…Other isoelectric forms of the type D prototoxin, with intermediate pIs, were observed. Previously, it has been shown that these forms are more toxic than the prototoxin but less toxic than the toxin (45), suggesting that activation is a multistep process involving sequential removal of short peptides from the N terminus of the prototoxin. Minor isoelectric forms of epsilon-toxin, with pIs of <5.4, were also seen.…”

Effect of Clostridium perfringens epsilon toxin on the cardiovascular system of rats

“…Habeeb (9) reported the extensive purification of the prototoxin from culture supernatant fluid of the organisms. Some investigators have reported various physicochemical properties of epsilon prototoxin and epsilon toxin (1,10,11,13,21). On the other hand, it has been reported that the toxin increases vascular permeability in the brain and the intestine, as well as lethality and necrosis (2,3,7,8).…”

Histidine residues in Clostridium perfringens epsilon toxin

“…perfringens epsilon toxin mediates lethal and necrotic activities. Habeeb [1,2] and Worthington et al [3] reported the physicochemical properties of the purified toxin. It also has been reported to increase vascular permeability in the brain [4] and the intestine [5] and to have pressor activity [6].…”