Chemical Synthesis, Backbone Cyclization and Oxidative Folding of Cystine-knot Peptides — Promising Scaffolds for Applications in Drug Design
Institute for Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Petersenstraße 22, D-64287 Darmstadt, Germany
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These authors contributed equally to this work.
Molecules 2012, 17(11), 12533-12552; https://doi.org/10.3390/molecules171112533
Received: 15 August 2012 / Revised: 19 September 2012 / Accepted: 22 October 2012 / Published: 24 October 2012
(This article belongs to the Special Issue Chemical Protein and Peptide Synthesis)
Cystine-knot peptides display exceptional structural, thermal, and biological stability. Their eponymous motif consists of six cysteine residues that form three disulfide bonds, resulting in a notably rigid structural core. Since they highly tolerate either rational or combinatorial changes in their primary structure, cystine knots are considered to be promising frameworks for the development of peptide-based pharmaceuticals. Despite their relatively small size (two to three dozens amino acid residues), the chemical synthesis route is challenging since it involves critical steps such as head-to-tail cyclization and oxidative folding towards the respective bioactive isomer. Herein we describe the topology of cystine-knot peptides, their synthetic availability and briefly discuss potential applications of engineered variants in diagnostics and therapy.
Keywords:
CCK; cyclotide; cystine knot; ICK; inhibitor; knottin; miniprotein; native chemical ligation; oxidative folding