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1WQD

An unusual fold for potassium channel blockers: NMR structure of three toxins from the scorpion Opisthacanthus madagascariensis

Summary for 1WQD
Entry DOI10.2210/pdb1wqd/pdb
Related1WQC 1WQE
DescriptorOmTx2 (1 entity in total)
Functional Keywordstoxin
Biological sourceOpisthacanthus madagascariensis
Total number of polymer chains1
Total formula weight3155.51
Authors
Chagot, B.,Pimentel, C.,Dai, L.,Pil, J.,Tytgat, J.,Nakajima, T.,Corzo, G.,Darbon, H.,Ferrat, G. (deposition date: 2004-09-28, release date: 2005-01-18, Last modification date: 2022-03-02)
Primary citationChagot, B.,Pimentel, C.,Dai, L.,Pil, J.,Tytgat, J.,Nakajima, T.,Corzo, G.,Darbon, H.,Ferrat, G.
An unusual fold for potassium channel blockers: NMR structure of three toxins from the scorpion Opisthacanthus madagascariensis
Biochem.J., 388:263-271, 2005
Cited by
PubMed Abstract: The Om-toxins are short peptides (23-27 amino acids) purified from the venom of the scorpion Opisthacanthus madagascariensis. Their pharmacological targets are thought to be potassium channels. Like Csalpha/beta (cystine-stabilized alpha/beta) toxins, the Om-toxins alter the electrophysiological properties of these channels; however, they do not share any sequence similarity with other scorpion toxins. We herein demonstrate by electrophysiological experiments that Om-toxins decrease the amplitude of the K+ current of the rat channels Kv1.1 and Kv1.2, as well as human Kv1.3. We also determine the solution structure of three of the toxins by use of two-dimensional proton NMR techniques followed by distance geometry and molecular dynamics. The structures of these three peptides display an uncommon fold for ion-channel blockers, Csalpha/alpha (cystine-stabilized alpha-helix-loop-helix), i.e. two alpha-helices connected by a loop and stabilized by two disulphide bridges. We compare the structures obtained and the dipole moments resulting from the electrostatic anisotropy of these peptides with those of the only other toxin known to share the same fold, namely kappa-hefutoxin1.
PubMed: 15631621
DOI: 10.1042/BJ20041705
PDB entries with the same primary citation
Experimental method
SOLUTION NMR
Structure validation

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