7QNB

Cryo-EM structure of human full-length beta3gamma2 GABA(A)R in complex with GABA and nanobody Nb25

7QNB の概要

• エントリーDOI: 10.2210/pdb7qnb/pdb
• EMDBエントリー: 14073
• 分子名称: Gamma-aminobutyric acid type A receptor subunit gamma2, Gamma-aminobutyric acid receptor subunit beta-3, Nanobody Nb25, ... (7 entities in total)
• 機能のキーワード: pentameric ligand-gated ion channel, neurotransmitter receptor, gaba receptor, membrane protein
• 由来する生物種: Homo sapiens (human); 詳細
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 291767.61

構造登録者

Sente, A.,Desai, R.,Naydenova, K.,Malinauskas, T.,Jounaidi, Y.,Miehling, J.,Zhou, X.,Masiulis, S.,Hardwick, S.W.,Chirgadze, D.Y.,Miller, K.W.,Aricescu, A.R. (登録日: 2021-12-20, 公開日: 2022-04-13, 最終更新日: 2024-11-13)

主引用文献

Sente, A.,Desai, R.,Naydenova, K.,Malinauskas, T.,Jounaidi, Y.,Miehling, J.,Zhou, X.,Masiulis, S.,Hardwick, S.W.,Chirgadze, D.Y.,Miller, K.W.,Aricescu, A.R.
Differential assembly diversifies GABA A receptor structures and signalling.
Nature, 604:190-194, 2022

PubMed Abstract: Type A γ-aminobutyric acid receptors (GABARs) are pentameric ligand-gated chloride channels that mediate fast inhibitory signalling in neural circuits and can be modulated by essential medicines including general anaesthetics and benzodiazepines. Human GABAR subunits are encoded by 19 paralogous genes that can, in theory, give rise to 495,235 receptor types. However, the principles that govern the formation of pentamers, the permutational landscape of receptors that may emerge from a subunit set and the effect that this has on GABAergic signalling remain largely unknown. Here we use cryogenic electron microscopy to determine the structures of extrasynaptic GABARs assembled from α4, β3 and δ subunits, and their counterparts incorporating γ2 instead of δ subunits. In each case, we identified two receptor subtypes with distinct stoichiometries and arrangements, all four differing from those previously observed for synaptic, α1-containing receptors. This, in turn, affects receptor responses to physiological and synthetic modulators by creating or eliminating ligand-binding sites at subunit interfaces. We provide structural and functional evidence that selected GABAR arrangements can act as coincidence detectors, simultaneously responding to two neurotransmitters: GABA and histamine. Using assembly simulations and single-cell RNA sequencing data, we calculated the upper bounds for receptor diversity in recombinant systems and in vivo. We propose that differential assembly is a pervasive mechanism for regulating the physiology and pharmacology of GABARs.

PubMed: 35355020
DOI: 10.1038/s41586-022-04517-3

実験手法

ELECTRON MICROSCOPY (3.1 Å)