7L6Q

Unliganded ELIC in styrene-maleic-acid nanodiscs at 2.5-Angstrom resolution

7L6Q の概要

• エントリーDOI: 10.2210/pdb7l6q/pdb
• EMDBエントリー: 23207
• 分子名称: Gamma-aminobutyric-acid receptor subunit beta-1, (1R)-2-{[(S)-{[(2S)-2,3-dihydroxypropyl]oxy}(hydroxy)phosphoryl]oxy}-1-[(hexadecanoyloxy)methyl]ethyl (9Z)-octadec-9-enoate, CARDIOLIPIN (3 entities in total)
• 機能のキーワード: pentameric ligand-gated ion channels, nanodisc, cys-loop receptor, styrene-maleic acid, membrane protein, protein-lipid interface
• 由来する生物種: Dickeya dadantii (strain 3937)
• タンパク質・核酸の鎖数: 5
• 化学式量合計: 195460.25

構造登録者

Grosman, C.,Kumar, P. (登録日: 2020-12-23, 公開日: 2021-06-23, 最終更新日: 2024-03-06)

主引用文献

Kumar, P.,Cymes, G.D.,Grosman, C.
Structure and function at the lipid-protein interface of a pentameric ligand-gated ion channel.
Proc.Natl.Acad.Sci.USA, 118:-, 2021

PubMed Abstract: Although it has long been proposed that membrane proteins may contain tightly bound lipids, their identity, the structure of their binding sites, and their functional and structural relevance have remained elusive. To some extent, this is because tightly bound lipids are often located at the periphery of proteins, where the quality of density maps is usually poorer, and because they may be outcompeted by detergent molecules used during standard purification procedures. As a step toward characterizing natively bound lipids in the superfamily of pentameric ligand-gated ion channels (pLGICs), we applied single-particle cryogenic electron microscopy to fragments of native membrane obtained in the complete absence of detergent-solubilization steps. Because of the heterogeneous lipid composition of membranes in the secretory pathway of eukaryotic cells, we chose to study a bacterial pLGIC (ELIC) expressed in 's inner membrane. We obtained a three-dimensional reconstruction of unliganded ELIC (2.5-Å resolution) that shows clear evidence for two types of tightly bound lipid at the protein-bulk-membrane interface. One of them was consistent with a "regular" diacylated phospholipid, in the cytoplasmic leaflet, whereas the other one was consistent with the tetra-acylated structure of cardiolipin, in the periplasmic leaflet. Upon reconstitution in polar-lipid bilayers, ELIC retained the functional properties characteristic of members of this superfamily, and thus, the fitted atomic model is expected to represent the (long-debated) unliganded-closed, "resting" conformation of this ion channel. Notably, the addition of cardiolipin to phosphatidylcholine membranes restored the ion-channel activity that is largely lost in phosphatidylcholine-only bilayers.

PubMed: 34083441
DOI: 10.1073/pnas.2100164118

実験手法

ELECTRON MICROSCOPY (2.5 Å)