8QQM

nicotinic acetylcholine receptor in intact synaptic membrane

8QQM の概要

• エントリーDOI: 10.2210/pdb8qqm/pdb
• EMDBエントリー: 18596 18785 18802 18804 18805 18816 18817 18823 18824 18831 18832 18835 18836 18837 18838 18840 18843 18844 18845 18846 18847 18849 18850 18853 18854 18855 18856 18857 18858 18862 18863 18865 18867 18869 18870
• 分子名称: Acetylcholine receptor subunit alpha, Acetylcholine receptor subunit delta, Acetylcholine receptor subunit beta, ... (4 entities in total)
• 機能のキーワード: ion channel, membrane protein
• 由来する生物種: Tetronarce californica (Pacific electric ray); 詳細
• タンパク質・核酸の鎖数: 5
• 化学式量合計: 268029.50

構造登録者

Unwin, N. (登録日: 2023-10-05, 公開日: 2024-05-08)

主引用文献

Unwin, N.
Influence of lipid bilayer on the structure of the muscle-type nicotinic acetylcholine receptor.
Proc.Natl.Acad.Sci.USA, 121:e2319913121-e2319913121, 2024

PubMed Abstract: The muscle-type nicotinic acetylcholine receptor is a transmitter-gated ion channel residing in the plasma membrane of electrocytes and striated muscle cells. It is present predominantly at synaptic junctions, where it effects rapid depolarization of the postsynaptic membrane in response to acetylcholine released into the synaptic cleft. Previously, cryo-EM of intact membrane from revealed that the lipid bilayer surrounding the junctional receptor has a uniquely asymmetric and ordered structure, due to a high concentration of cholesterol. It is now shown that this special lipid environment influences the transmembrane (TM) folding of the protein. All five submembrane MX helices of the membrane-intact junctional receptor align parallel to the surface of the cholesterol-ordered lipids in the inner leaflet of the bilayer; also, the TM helices in the outer leaflet are splayed apart. However in the structure obtained from the same protein after extraction and incorporation in nanodiscs, the MX helices do not align to a planar surface, and the TM helices arrange compactly in the outer leaflet. Realignment of the MX helices of the nanodisc-solved structure to a planar surface converts their adjoining TM helices into an obligatory splayed configuration, characteristic of the junctional receptor. Thus, the form of the receptor sustained by the special lipid environment of the synaptic junction is the one that mediates fast synaptic transmission; whereas, the nanodisc-embedded protein may be like the extrajunctional form, existing in a disordered lipid environment.

PubMed: 38683987
DOI: 10.1073/pnas.2319913121

実験手法

ELECTRON MICROSCOPY (4.7 Å)