SPATIAL STRUCTURE OF THE NEUROTOXIN M9 BUTHUS-EUPEUS IN SOLUTION AS REVEALED BY THE H-1-NMR SPECTROSCOPY

  • 1 October 1986
    • journal article
    • research article
    • Vol. 12  (10) , 1306-1316
Abstract
Neurotoxin M9 isolated from the venom of Central Asian scorpion Buthus eupeus (66 amino acid residues, 4 disulfide bridge) has two slowly exchangeable conformations at the acid pH. 2D-1H-NMR spectroscopy has been used to determine the polypeptide backbone folding in the conformer that dominates under physiological conditions. The conformer contains the right .alpha.-helix (residues 22-31) and the antiparallel .beta.-sheet, which consists of the three strands (residues 1-5, 46-52, 35-40). All five Xxx-Pro bonds are the the trans configuration. Comparison of the obtained data with the crystal structure of the homologous scorpion toxin v-3 Centruroides sculpturatus (65 residues) and the solution spatial structure of the .mchlt.short.mchgt. type insectotoxin I5A Buthus eupeus (35 residues) show close similarity in the first case and similarity of the types and mutual disposition of the regular secondary structure elements in the second case.

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