Synthesis and characterization of amino acid deletion analogs of κ-hefutoxin 1, a scorpion toxin on potassium channels

Nine analogs of scorpion toxin peptide κ-hefutoxin 1 were synthesized by stepwise deletion of its amino acid residues. Disulfide bond pairings of the synthetic analogs were confirmed by enzymatic digestion followed by MALDI-TOF-MS measurements. Functional characterization shows that analogs in which N-terminal residues were deleted retained biological activity, whereas deletion of middle part residues resulted in loss of activity. Furthermore, κ-hefutoxin 1 and analogs were subjected to a screening on voltage-gated potassium channels in order to determine their subtype selectivity. It is shown that κ-hefutoxin 1 is suitable as template for peptidomimetics in order to design small peptide-based therapeutic compounds.