1BMR
ALPHA-LIKE TOXIN LQH III FROM SCORPION LEIURUS QUINQUESTRIATUS HEBRAEUS, NMR, 25 STRUCTURES
Summary for 1BMR
| Entry DOI | 10.2210/pdb1bmr/pdb |
| Descriptor | LQH III ALPHA-LIKE TOXIN (1 entity in total) |
| Functional Keywords | alpha-like toxin, scorpion toxin, sodium channel inhibitor, toxin |
| Biological source | Leiurus quinquestriatus hebraeus |
| Total number of polymer chains | 1 |
| Total formula weight | 7063.99 |
| Authors | Krimm, I.,Gilles, N.,Sautiere, P.,Stankiewicz, M.,Pelhate, M.,Gordon, D.,Lancelin, J.-M. (deposition date: 1998-07-24, release date: 1999-02-16, Last modification date: 2024-11-20) |
| Primary citation | Krimm, I.,Gilles, N.,Sautiere, P.,Stankiewicz, M.,Pelhate, M.,Gordon, D.,Lancelin, J.M. NMR structures and activity of a novel alpha-like toxin from the scorpion Leiurus quinquestriatus hebraeus. J.Mol.Biol., 285:1749-1763, 1999 Cited by PubMed Abstract: NMR structures of a new toxin from the scorpion Leiurus quinquestriatus hebraeus (Lqh III) have been investigated in conjunction with its pharmacological properties. This toxin is proposed to belong to a new group of scorpion toxins, the alpha-like toxins that target voltage-gated sodium channels with specific properties compared with the classical alpha-scorpion toxins. Electrophysiological analysis showed that Lqh III inhibits a sodium current inactivation in the cockroach axon, but induces in addition a resting depolarization due to a slowly decaying tail current atypical to other alpha-toxin action. Binding studies indicated that radiolabeled Lqh III binds with a high degree of affinity (Ki=2.2 nM) on cockroach sodium channels and that the alpha-toxin from L quinquestriatus hebraeus highly active on insects (LqhalphaIT) and alpha-like toxins compete at low concentration for its receptor binding site, suggesting that the alpha-like toxin receptor site is partially overlapping with the receptor site 3. Conversely, in rat brain, Lqh III competes for binding of the most potent anti-mammal alpha-toxin from Androctonus australis Hector venom (AaH II) only at very high concentration. The NMR structures were used for the scrutiny of the similarities and differences with representative scorpion alpha-toxins targeting the voltage-gated sodium channels of either mammals or insects. Three turn regions involved in the functional binding site of the anti-insect LqhalphaIT toxin reveal significant differences in the Lqh III structure. The electrostatic charge distribution in the Lqh III toxin is also surprisingly different when compared with the anti-mammal alpha-toxin AaH II. Similarities in the electrostatic charge distribution are, however, recognized between alpha-toxins highly active on insects and the alpha-like toxin Lqh III. This affords additional important elements to the definition of the new alpha-like group of scorpion toxins and the mammal versus insect scorpion toxin selectivities. PubMed: 9917409DOI: 10.1006/jmbi.1998.2418 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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