4AQ9
Gating movement in acetylcholine receptor analysed by time- resolved electron cryo-microscopy (open class)
Summary for 4AQ9
| Entry DOI | 10.2210/pdb4aq9/pdb |
| Related | 1L4W 1LJZ 1OED 2BG9 4AQ5 |
| EMDB information | 2072 |
| Descriptor | ACETYLCHOLINE RECEPTOR SUBUNIT ALPHA, ACETYLCHOLINE RECEPTOR BETA SUBUNIT, ACETYLCHOLINE RECEPTOR DELTA SUBUNIT, ... (4 entities in total) |
| Functional Keywords | membrane protein, freeze-trapping, asymmetric gating, allosteric mechanism |
| Biological source | TORPEDO MARMORATA (MARBLED ELECTRIC RAY) More |
| Total number of polymer chains | 5 |
| Total formula weight | 278066.90 |
| Authors | Unwin, N.,Fujiyoshi, Y. (deposition date: 2012-04-13, release date: 2012-08-01, Last modification date: 2024-11-06) |
| Primary citation | Unwin, N.,Fujiyoshi, Y. Gating Movement of Acetylcholine Receptor Caught by Plunge-Freezing. J.Mol.Biol., 422:617-, 2012 Cited by PubMed Abstract: The nicotinic acetylcholine (ACh) receptor converts transiently to an open-channel form when activated by ACh released into the synaptic cleft. We describe here the conformational change underlying this event, determined by electron microscopy of ACh-sprayed and freeze-trapped postsynaptic membranes. ACh binding to the α subunits triggers a concerted rearrangement in the ligand-binding domain, involving an ~1-Å outward displacement of the extracellular portion of the β subunit where it interacts with the juxtaposed ends of α-helices shaping the narrow membrane-spanning pore. The β-subunit helices tilt outward to accommodate this displacement, destabilising the arrangement of pore-lining helices, which in the closed channel bend inward symmetrically to form a central hydrophobic gate. Straightening and tangential motion of the pore-lining helices effect channel opening by widening the pore asymmetrically and increasing its polarity in the region of the gate. The pore-lining helices of the α(γ) and δ subunits, by flexing between alternative bent and straight conformations, undergo the greatest movements. This coupled allosteric transition shifts the structure from a tense (closed) state toward a more relaxed (open) state. PubMed: 22841691DOI: 10.1016/J.JMB.2012.07.010 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (6.2 Å) |
Structure validation
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