A surface plasmon resonance approach to monitor toxin interactions with an isolated voltage-gated sodium channel paddle motif |
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| Authors: | Marie-France Martin-Eauclaire Géraldine Ferracci Frank Bosmans Pierre E. Bougis |
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| Affiliation: | 1.Centre National de la Recherche Scientifique, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseillle, Unité Mixte de Recherche 7286, Plates-Formes de Recherche en Neurosciences-Centre d’Analyse Protéomique de Marseille, Aix Marseille Université, 13344 Marseille, France;2.Department of Physiology, and 3.Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205 |
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| Abstract: | Animal toxins that inhibit voltage-gated sodium (Nav) channel fast inactivation can do so through an interaction with the S3b–S4 helix-turn-helix region, or paddle motif, located in the domain IV voltage sensor. Here, we used surface plasmon resonance (SPR), an optical approach that uses polarized light to measure the refractive index near a sensor surface to which a molecule of interest is attached, to analyze interactions between the isolated domain IV paddle and Nav channel–selective α-scorpion toxins. Our SPR analyses showed that the domain IV paddle can be removed from the Nav channel and immobilized on sensor chips, and suggest that the isolated motif remains susceptible to animal toxins that target the domain IV voltage sensor. As such, our results uncover the inherent pharmacological sensitivities of the isolated domain IV paddle motif, which may be exploited to develop a label-free SPR approach for discovering ligands that target this region. |
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