Disulfide-rich peptides, evolved as small yet potent modulators, interact with an array of receptors, notably ion channels. Intriguingly, these peptides often exert their modulatory effects through allosteric mechanisms, binding to regions peripheral to the ion-conduction pathway.

Investigating these interactions at atomic resolution can be challenging due to the inherent instability of these complex membrane protein receptors. A viable approach circumventing this issue is to isolate and study the peptide binding region of these ion channels, thereby simplifying the problem substantially.

This presentation will discuss our recent work on the stabilisation of allosteric binding sites within voltage-gated ion channels and acid-sensing channels. We have employed NMR spectroscopy and isothermal titration calorimetry to characterise the structure and peptide binding properties of these sites, offering new insights into the mechanism of action of peptide modulators of ion channels.

Furthermore, our results reveal how modulating the environment of the ion channel segment can lead to altered peptide binding properties. These observations align with functional studies and underscore the importance of state-selective disulfide-rich peptides. These peptides serve as valuable tools in validating the conformational states of deconstructed ion channels and lay the groundwork for the development of novel ion channel screening platforms.