ジャーナル: Nature / 年: 2014 タイトル: Structural mechanism of glutamate receptor activation and desensitization. 著者: Joel R Meyerson / Janesh Kumar / Sagar Chittori / Prashant Rao / Jason Pierson / Alberto Bartesaghi / Mark L Mayer / Sriram Subramaniam / 要旨: Ionotropic glutamate receptors are ligand-gated ion channels that mediate excitatory synaptic transmission in the vertebrate brain. To gain a better understanding of how structural changes gate ion ...Ionotropic glutamate receptors are ligand-gated ion channels that mediate excitatory synaptic transmission in the vertebrate brain. To gain a better understanding of how structural changes gate ion flux across the membrane, we trapped rat AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) and kainate receptor subtypes in their major functional states and analysed the resulting structures using cryo-electron microscopy. We show that transition to the active state involves a 'corkscrew' motion of the receptor assembly, driven by closure of the ligand-binding domain. Desensitization is accompanied by disruption of the amino-terminal domain tetramer in AMPA, but not kainate, receptors with a two-fold to four-fold symmetry transition in the ligand-binding domains in both subtypes. The 7.6 Å structure of a desensitized kainate receptor shows how these changes accommodate channel closing. These findings integrate previous physiological, biochemical and structural analyses of glutamate receptors and provide a molecular explanation for key steps in receptor gating.
pH: 8 詳細: 150 mM NaCl, 20 mM Tris pH 8.0, 0.75 mM DDM, 0.12 mM CHS, 1 mM quisqualic acid
グリッド
詳細: Vitrified specimens were prepared by adding 2.5 uL of liganded protein at 1.8 mg/ml to R2/2 holey carbon grids (Quantifoil, Jena, Germany) rendered hydrophilic by chemical treatment to enable ...詳細: Vitrified specimens were prepared by adding 2.5 uL of liganded protein at 1.8 mg/ml to R2/2 holey carbon grids (Quantifoil, Jena, Germany) rendered hydrophilic by chemical treatment to enable particle distribution into the holes (Meyerson JR, Rao P, Kumar K, Chittori S, Banerjee S, Pierson J, Mayer ML, and Subramaniam S, manuscript in preparation).
凍結
凍結剤: ETHANE / チャンバー内湿度: 100 % / チャンバー内温度: 120 K / 装置: FEI VITROBOT MARK IV / 手法: Blot for 2 seconds before plunging
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
日付
2013年8月1日
撮影
カテゴリ: CCD フィルム・検出器のモデル: FEI FALCON II (4k x 4k) 実像数: 888 / 平均電子線量: 25 e/Å2