Fig 4.

Number of amino acid changes at each domain of the three ChxA toxinotypes in comparison to the prototype sequence (AY876053). The length of ChxA peptide is 634 amino acids for ChxA I and 633 for ChxA III. The peptide length of ChxA II varies from 628 to 633 amino acids. The receptor binding domain (RBD) of ChxA II with 34 to 38 amino acid changes and the catalytic domain (CD) of ChxA III with 29 to 32 amino acid changes are the most diverse domains. TD, translocation domain; UFD, unknown function domain. †, common deletion of 6 amino acids in all strains; ‡, insertion of 5 amino acids in 6 strains; ¶, deletion of 1 amino acid in all strains.