ペンタメリックのリガンドゲートイオンチャネルのX線構造は,明らかに開いた形状の形状である
Nicolas Bocquet1, Hugues Nury, Marc Baaden
1Pasteur Institute, G5 Group of Channel-Receptor, CNRS URA 2182.
Nature
|November 7, 2008
まとめ
研究者らは,Gloeobacter violaceus pentamericのリガンドゲートイオンチャネル (GLIC) のX線構造をオープン状態で明らかにした. これは,ガッティングメカニズムとCysループチャネルのイオン浸透に関する洞察を提供します.
科学分野:
- 構造生物学 構造生物学とは
- 膜タンパク質の生物物理学
- イオンチャネル機能のイオンチャネル機能
背景:
- ペンタミクスのリガンドゲートイオンチャネル (LGIC) は,神経細胞の急速な信号伝達に不可欠です.
- イオン浸透とチャネルゲーティングの正確なメカニズムを理解することは,膜タンパク質研究における重要な課題であり続けています.
研究 の 目的:
- イオンチャネルゲートと貫通の構造的基礎を解明する.
- グロオバクター・ヴァイオラセウス (Gloeobacter violaceus) のリガンドゲートイオンチャネル (GLIC) の高解像度X線構造を,開いた形状で提示する.
主な方法:
- 2.9 Å の解像度のX線結晶学.
- ELICチャネルとの構造的な比較.
- 毛孔構造と残留物の分布の分析.
主要な成果:
- GLIC構造は,外側に開いて,内側に水性残留物によって収縮された,イオン選択性のメカニズムを示唆する,トンネル状のトランスメブラン孔を明らかにします.
- ELIC (閉じた状態) と比較すると,GLICは毛孔が広く,水嫌性の収縮がないことがわかります.
- チャンネル開きには,細胞外ドメインの固体回転と,トランスメブランヘリックス (M2,M3) の方向転換が含まれます.
結論:
- GLIC構造は,オープンなCysループチャネルの詳細な見方を提供し,陽子活性化に関する洞察を提供します.
- この発見は,四次 (ドメイン回転) と三次 (ヘリックス再配置) の構造変化の両方を含むゲーティングモデルを支持する.
- この研究は,イオンチャネルメカニズムに関する理解を深め,関連するチャネルのための構造的なテンプレートを提供します.
関連する概念動画
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
Ligand-gated Ion Channels
Ligand-gated ion channels are transmembrane proteins with a channel for ions to pass through and a binding site for a ligand. The channel opens only when a ligand attaches to the binding site.
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
Ligand-gated Ion Channels
Ligand-gated ion channels are transmembrane proteins with a channel for ions to pass through and a binding site for a ligand. The channel opens only when a ligand attaches to the binding site.
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
Ion Channels
The movement of ions like sodium, potassium, and calcium into and out of the cell is essential to maintain the electrochemical gradient in living cells. The ion channels—a class of membrane transport proteins—help maintain this ionic gradient for the smooth functioning of physiological activities such as maintaining cell size and volume, conducting nerve impulses, and gas and nutrient exchange.
Ion channels are specialized integral membrane proteins on the plasma membrane that allow specific...
Ion channels are specialized integral membrane proteins on the plasma membrane that allow specific...
Crystal Field Theory - Octahedral Complexes
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
Voltage-gated Ion Channels
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...


