NMR structures of the transmembrane domains of the ?4?2 nAChR.

ABSTRACT: The ?4?2 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 ?4?2 and other neuronal nAChRs is presently limited. In this study, we determined structures of the transmembrane (TM) domains of the ?4 and ?2 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 ?4 and ?2 interacted with each other and spontaneously formed pentameric assemblies in the LDAO micelles. The Na(+) flux assay revealed that ?4?2 formed Na(+) permeable channels in lipid vesicles. Efflux of Na(+) through the ?4?2 channels reduced intra-vesicle Sodium Green™ fluorescence in a time-dependent manner that was not observed in vesicles without incorporating ?4?2. The study provides structural insight into the TM domains of the ?4?2 nAChR. It offers a valuable structural framework for rationalizing extensive biochemical data collected previously on the ?4?2 nAChR and for designing new therapeutic modulators.

SUBMITTER: Bondarenko V 

PROVIDER: S-EPMC3319252 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature