Structure and action of the nicotinic acetylcholine receptor explored by electron microscopy.
The nicotinic acetylcholine (ACh) receptor is the transmitter-gated ion channel at the nerve/muscle synapse. Electron microscopical experiments on isolated postsynaptic membranes have determined the structure of this channel and how the structure changes upon activation. When ACh enters the ligand-binding domain it initiates rotations of the protein chains on opposite sides of the entrance to the membrane-spanning pore. These rotations are communicated to the pore-lining alpha-helices and open the gate--a constricting hydrophobic girdle at the middle of the membrane--by breaking it apart. The movements are small and involve energetically favourable displacements parallel to the membrane plane.
Unwin
Nigel
N
MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK. mas@mrc-lmb.cam.ac.uk
D000818:Animals; D004557:Electric Organ / Q000378:metabolism; D066298:In Vitro Techniques; D015640:Ion Channel Gating; D008854:Microscopy, Electron; D008958:Models, Molecular; D011487:Protein Conformation; D021122:Protein Subunits; D011978:Receptors, Nicotinic / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure*; D012399:Rotation; D014101:Torpedo
D021122:Protein Subunits; D011978:Receptors, Nicotinic