Acetylcholine receptor channel imaged in the open state.
The structure of the open-channel form of the acetylcholine receptor has been determined from electron images of Torpedo ray postsynaptic membranes activated by brief (< 5 ms) mixing with droplets containing acetylcholine. Comparison with the closed-channel form shows that acetylcholine initiates small rotations of the subunits in the extracellular domain, which trigger a change in configuration of alpha-helices lining the membrane-spanning pore. The open pore tapers towards the intracellular membrane face, where it is shaped by a 'barrel' of alpha-helices having a pronounced right-handed twist.
Unwin
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MRC Laboratory of Molecular Biology, Cambridge, UK.
D000109:Acetylcholine; D000818:Animals; D005293:Ferritins; D005615:Freezing; D007091:Image Processing, Computer-Assisted; D015640:Ion Channel Gating; D007477:Ions; D010539:Permeability; D011978:Receptors, Nicotinic / Q000648:ultrastructure*; D013570:Synaptic Membranes / Q000648:ultrastructure; D014101:Torpedo
D007477:Ions; D011978:Receptors, Nicotinic; D005293:Ferritins; D000109:Acetylcholine