Mineev KS, Chernykh MA, Motov VV, Prudnikova DA, Pavlenko DM, Kuzmenkov AI, Peigneur S, Tytgat J, Vassilevski AA. A scorpion toxin affecting sodium channels shows double cis-trans isomerism.
FEBS Lett 2023;
597:2358-2368. [PMID:
37501371 DOI:
10.1002/1873-3468.14705]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 07/14/2023] [Indexed: 07/29/2023]
Abstract
Scorpion α-toxins (α-NaTx) inhibiting the inactivation of voltage-gated sodium channels (Nav ) are a well-studied family of small proteins. We previously showed that the structure of α-NaTx specificity module responsible for selective Nav binding is governed by an interplay between the nest and niche protein motifs. Here, we report the solution structure of the toxin Lqq4 from the venom of the scorpion Leiurus quinquestriatus. Unexpectedly, we find that this toxin presents an ensemble of long-lived structurally distinct states. We unequivocally assign these states to the alternative configurations (cis-trans isomers) of two peptide bonds: V56-P57 and C17-G18; neither of the cis isomers has been described in α-NaTx so far. We argue that the native conformational space of α-NaTx is wider than assumed previously.
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