4AQ5

Gating movement in acetylcholine receptor analysed by time-resolved electron cryo-microscopy (closed class)

4AQ5 の概要

• エントリーDOI: 10.2210/pdb4aq5/pdb
• 関連するPDBエントリー: 1L4W 1LJZ 1OED 2BG9 4AQ9
• EMDBエントリー: 2071
• 分子名称: ACETYLCHOLINE RECEPTOR SUBUNIT ALPHA, ACETYLCHOLINE RECEPTOR BETA SUBUNIT, ACETYLCHOLINE RECEPTOR DELTA SUBUNIT, ... (4 entities in total)
• 機能のキーワード: membrane protein, freeze-trapping, asymmetric gating, allosteric mechanism
• 由来する生物種: TORPEDO MARMORATA (MARBLED ELECTRIC RAY); 詳細
• タンパク質・核酸の鎖数: 5
• 化学式量合計: 278066.90

構造登録者

Unwin, N.,Fujiyoshi, Y. (登録日: 2012-04-12, 公開日: 2012-08-01, 最終更新日: 2024-11-20)

主引用文献

Unwin, N.,Fujiyoshi, Y.
Gating Movement of Acetylcholine Receptor Caught by Plunge-Freezing.
J.Mol.Biol., 422:617-, 2012

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: 22841691
DOI: 10.1016/J.JMB.2012.07.010

実験手法

ELECTRON MICROSCOPY (6.2 Å)