Synthesis of mu-conotoxin GIIIA: a chemical probe for sodium channels

mu-Conotoxin GIIIA, a 22 amino acid peptide paralytic toxin which inhibits the muscle voltage-activated sodium channels, was synthesized by a solid phase method. No purification of intermediates was necessary for the synthesis, and a simple air oxidation of the deprotected crude peptide gave the desired toxin. By all criteria applied, the synthetic material was indistinguishable from the authentic natural toxin.