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Updated: Aug 8, 2026

Synthesis and Structure Determination of µ-Conotoxin PIIIA Isomers with Different Disulfide Connectivities
Published on: October 2, 2018
The synthesis, structural characterization, and receptor specificity of the alpha-conotoxin Vc1.1
Richard J Clark1, Harald Fischer, Simon T Nevin
1Institute for Molecular Bioscience and School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia.
Abstract:
The alpha-conotoxin Vc1.1 is a small disulfide-bonded peptide currently in development as a treatment for neuropathic pain. This study describes the synthesis, determination of the disulfide connectivity, and the determination of the three-dimensional structure of Vc1.1 using NMR spectroscopy. Vc1.1 was shown to inhibit nicotine-evoked membrane currents in isolated bovine chromaffin cells in a concentration-dependent manner and preferentially targets peripheral nicotinic acetylcholine receptor (nAChR) subtypes over central subtypes. Specifically, Vc1.1 is selective for alpha3-containing nAChR subtypes. The three-dimensional structure of Vc1.1 comprises a small alpha-helix spanning residues Pro6 to Asp11 and is braced by the I-III, II-IV disulfide connectivity seen in other alpha-conotoxins. A comparison of the structure of Vc1.1 with other alpha-conotoxins, taken together with nAChR selectivity data, suggests that the conserved proline at position 6 is important for binding, whereas a number of residues in the C-terminal portion of the peptide contribute toward the selectivity. The structure reported here should open new opportunities for further development of Vc1.1 or analogues as analgesic agents.
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