it has four disulfide bridges and its scaffold is formed by a single α-helix, and a three-stranded β-sheet structure. typical for css β-toxins, no methionine and isoleucine amino acids occur in the miniprotein. cssii’s characteristics include the replacement of proline in position 59 with tyrosine, differentiating it from all other α- and β-toxins. moreover, glutamine (position 32) and histidine (position 57) replace lysine and glycine residues respectively, differentiating cssii from all other β-toxins. the protein is amidated at the c-terminal end.