Enhanced microwave‐assisted method for on‐bead disulfide bond formation: Synthesis of α‐conotoxin MII

Abstract

A novel enhanced microwave‐assisted disulfide bridge formation method has been developed. To optimize the synthesis of the biologically important bicyclic peptide α‐conotoxin MII (α‐CtxMII), several cyclization methods have been tested and are discussed herein. By using m.w.‐assisted heating, we achieved high yields for the first loop cyclization of α‐CtxMII on‐bead. This method has the advantage of avoiding intermolecular by‐products during the cyclization step. Furthermore, the method gives higher yields compared with the common on‐bead cyclization methods. The second disulfide bridge of α‐CtxMII was formed using a simple oxidation method after the cleavage of the intermediate monocyclic peptide from the resin. This method has the potential to be efficient for the synthesis of other disulfide rich biologically important peptides. © 2008 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 92: 23–34, 2009.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com