title: NMR structures of the transmembrane domains of the α4β2 nAChR.
abstract: The α4β2 nicotinic acetylcholine receptor (nAChR) is the predominant heteromeric subtype of nAChRs in the brain, which has been implicated in numerous neurological conditions. The structural information specifically for the α4β2 and other neuronal nAChRs is presently limited. In this study, we determined structures of the transmembrane (TM) domains of the α4 and β2 subunits in lauryldimethylamine-oxide (LDAO) micelles using solution NMR spectroscopy. NMR experiments and size exclusion chromatography-multi-angle light scattering (SEC-MALS) analysis demonstrated that the TM domains of α4 and β2 interacted with each other and spontaneously formed pentameric assemblies in the LDAO micelles. The Na(+) flux assay revealed that α4β2 formed Na(+) permeable channels in lipid vesicles. Efflux of Na(+) through the α4β2 channels reduced intra-vesicle Sodium Green™ fluorescence in a time-dependent manner that was not observed in vesicles without incorporating α4β2. The study provides structural insight into the TM domains of the α4β2 nAChR. It offers a valuable structural framework for rationalizing extensive biochemical data collected previously on the α4β2 nAChR and for designing new therapeutic modulators.
authors.affiliation: Department of Anesthesiology, University of Pittsburgh, School of Medicine, PA 15260, USA.
authors.forename: Vasyl
authors.initials: V
authors.lastname: Bondarenko
authors.forename: David
authors.initials: D
authors.lastname: Mowrey
authors.forename: Tommy
authors.initials: T
authors.lastname: Tillman
authors.forename: Tanxing
authors.initials: T
authors.lastname: Cui
authors.forename: Lu Tian
authors.initials: LT
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.forename: Pei
authors.initials: P
authors.lastname: Tang
mesh_terms: D004123:Dimethylamines / Q000737:chemistry; D006801:Humans; D017136:Ion Transport / Q000502:physiology; D008823:Micelles; D019906:Nuclear Magnetic Resonance, Biomolecular; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011978:Receptors, Nicotinic / Q000737:chemistry* / Q000378:metabolism; D012964:Sodium / Q000737:chemistry / Q000378:metabolism
chemical_list: D004123:Dimethylamines; D008823:Micelles; D011978:Receptors, Nicotinic; C403531:nicotinic receptor alpha4beta2; C014518:dodecyldimethylamine oxide; D012964:Sodium