Natural Neurotoxins in the Study of the Spatial Structure of Nicotinic Acetylcholine Receptors—the Main Milestones

Nicotinic acetylcholine receptors (nAChRs) belong to the superfamily of ligand-gated ion channels and are among the most studied neurotransmitter receptors. They play an important role in nerve impulse transmission in the central and peripheral nervous systems and are also involved in regulating the functions of other systems, including the immune and cardiovascular ones. This review presents the main stages of elucidating the spatial structure of nAChRs, including a detailed characterization of their ligand-binding sites using natural and synthetic neurotoxins. These stages cover, in particular, the localization of binding sites on the receptor using modified ligands, crystallographic studies of various structural homologs of the receptor, including complexes with toxins, as well as recent cryoelectron microscopy data.