National Institutes of Health/National Institute on Drug Abuse (NIH/NIDA)
米国
引用
ジャーナル: Neuron / 年: 2020 タイトル: Structure of the Native Muscle-type Nicotinic Receptor and Inhibition by Snake Venom Toxins. 著者: Md Mahfuzur Rahman / Jinfeng Teng / Brady T Worrell / Colleen M Noviello / Myeongseon Lee / Arthur Karlin / Michael H B Stowell / Ryan E Hibbs / 要旨: The nicotinic acetylcholine receptor, a pentameric ligand-gated ion channel, converts the free energy of binding of the neurotransmitter acetylcholine into opening of its central pore. Here we ...The nicotinic acetylcholine receptor, a pentameric ligand-gated ion channel, converts the free energy of binding of the neurotransmitter acetylcholine into opening of its central pore. Here we present the first high-resolution structure of the receptor type found in muscle-endplate membrane and in the muscle-derived electric tissues of fish. The native receptor was purified from Torpedo electric tissue and functionally reconstituted in lipids optimal for cryo-electron microscopy. The receptor was stabilized in a closed state by the binding of α-bungarotoxin. The structure reveals the binding of a toxin molecule at each of two subunit interfaces in a manner that would block the binding of acetylcholine. It also reveals a closed gate in the ion-conducting pore, formed by hydrophobic amino acid side chains, located ∼60 Å from the toxin binding sites. The structure provides a framework for understanding gating in ligand-gated channels and how mutations in the acetylcholine receptor cause congenital myasthenic syndromes.