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Updated: Jul 20, 2026

Synthesis and Structure Determination of µ-Conotoxin PIIIA Isomers with Different Disulfide Connectivities
Published on: October 2, 2018
1H-NMR signal assignments and secondary structure analysis of martentoxin
1Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
Abstract:
Martentoxin is a peptide of 37 amino acid residues purified from the venom of the Chinese scorpion Buthus martensi Karch, which has been demonstrated to be an inhibitor of voltage-dependent sodium channel and voltage-dependent delayed rectifier potassium channel. To elucidate the molecular mechanism of this interaction, the structure of martentoxin was studied by 2D-NMR. The secondary structure of martentoxin consists of a triple-stranded beta-sheet connected to a alpha-helical structure. This helix encompasses 10 residues from Ser11 to Lys20. The three strands of beta-sheet probably comprise residues Gly2-Asp5, Q27-N30 and Glu33-Cys36, Cys30-Asn33 with a type I'beta turn centered on Asn31-Asn32. The results indicate that martentoxin possesses the conserved beta alpha beta beta structure of all the potassium channel toxins.
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