Role of one tryptophan residue in the lethal activity of Clostridium perfringens epsilon toxin.

The lethal activity of Clostridium perfringens epsilon toxin was inactivated by N-bromosuccinimide and N-chlorosuccinimide. Amino acid analysis of N-bromosuccinimide-treated prototoxin indicated that the one tryptophan residue present in the protein was abolished, and methionine and tyrosine reduced markedly. N-chloro-succinimide-treated prototoxin lost completely both tryptophan and methionine residues. The toxin was not inactivated by chloramine T, but all of methionine residues present in the protein was found to be oxidized by the agent. The data suggest that the one tryptophan residue present in the toxin is important for the lethal activity.