Structure-Activity Relationship of a Heat-Stable Enterotoxin Produced by Yersinia enterocolitica

Several shorter analogues of heat-stable enterotoxin (ST) produced by Yersinia enterocolitica were synthesized by a conventional method and their toxicities were examined by using suckling mice. The full enterotoxigenic activity of ST of Y. enterocolitica was found to be carried on a peptide, which consists of 13 amino acid residues from the 18th Cys to the C-terminal Cys and has a similar amino acid sequence to those of ST’s produced by enterotoxigenic Escherichia coli (S. Aimoto et al., Eur. J. Biochem., 129, 257 (1982)) and Vibrio cholerae non-01 (T. Takao et al., FEBS Lett., 193, 250 (1985)). The results imply that the structural elements for expression of the toxicity are present in the common amino acid sequences of ST’s of Y. enterocolitica, E. coli, and V. cholerae non-01.