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Crystal structure of the extracellular domain of alpha2 nicotinic acetylcholine receptor in pentameric assemblyCrystal structure of the extracellular domain of alpha2 nicotinic acetylcholine receptor in pentameric assembly
Structural highlights
DiseaseACHA2_HUMAN Autosomal dominant nocturnal frontal lobe epilepsy. The disease is caused by mutations affecting the gene represented in this entry. FunctionACHA2_HUMAN After binding acetylcholine, the AChR responds by an extensive change in conformation that affects all subunits and leads to opening of an ion-conducting channel across the plasma membrane. Publication Abstract from PubMedIn this study we report the X-ray crystal structure of the extracellular domain (ECD) of the human neuronal alpha2 nicotinic acetylcholine receptor (nAChR) subunit in complex with the agonist epibatidine at 3.2 A. Interestingly, alpha2 was crystallized as a pentamer, revealing the intersubunit interactions in a wild type neuronal nAChR ECD and the full ligand binding pocket conferred by two adjacent alpha subunits. The pentameric assembly presents the conserved structural scaffold observed in homologous proteins, as well as distinctive features, providing unique structural information of the binding site between principal and complementary faces. Structure-guided mutagenesis and electrophysiological data confirmed the presence of the alpha2(+)/alpha2(-) binding site on the heteromeric low sensitivity alpha2beta2 nAChR and validated the functional importance of specific residues in alpha2 and beta2 nAChR subunits. Given the pathological importance of the alpha2 nAChR subunit and the high sequence identity with alpha4 (78%) and other neuronal nAChR subunits, our findings offer valuable information for modeling several nAChRs and ultimately for structure-based design of subtype specific drugs against the nAChR associated diseases. Crystal structure of a human neuronal nAChR extracellular domain in pentameric assembly: Ligand-bound alpha2 homopentamer.,Kouvatsos N, Giastas P, Chroni-Tzartou D, Poulopoulou C, Tzartos SJ Proc Natl Acad Sci U S A. 2016 Aug 23;113(34):9635-40. doi:, 10.1073/pnas.1602619113. Epub 2016 Aug 4. PMID:27493220[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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