1WQD
An unusual fold for potassium channel blockers: NMR structure of three toxins from the scorpion Opisthacanthus madagascariensis
Summary for 1WQD
| Entry DOI | 10.2210/pdb1wqd/pdb |
| Related | 1WQC 1WQE |
| Descriptor | OmTx2 (1 entity in total) |
| Functional Keywords | toxin |
| Biological source | Opisthacanthus madagascariensis |
| Total number of polymer chains | 1 |
| Total formula weight | 3155.51 |
| 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: 2024-11-13) |
| Primary citation | Chagot, 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: 15631621DOI: 10.1042/BJ20041705 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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