レーザー誘発のpHジャンプによって研究されたM2プロトンチャネルのプロトン輸送機構
Ban-Seok Jeong1, R Brian Dyer1
1Department of Chemistry, Emory University , Atlanta, Georgia 30322, United States.
Journal of the American Chemical Society
|May 4, 2017
まとめ
インフルエンザAウイルスのM2チャンネル
科学分野:
- バイオ物理学
- 構造生物学
- ウイルス学
背景:
- インフルエンザAウイルスのM2陽子チャネルは,ウイルスの脱毛に不可欠です.
- 高い選択性と低pHでの単方向性のある陽子輸送により,重要な研究モデルとなっています.
- しかし,pH依存のゲートと陽子伝導の正確なメカニズムは不明である.
研究 の 目的:
- 陽子チャンネルM2の活性化プロセスを直接観察する.
- pH依存のゲートと陽子伝導の分子詳細を解明する.
主な方法:
- レーザーによる pH ジャンプ技術を使った
- トリプトファンの光がチャンネル活性化を監視する探査機として使われた.
- プロトネーションとコンフォメーションの変化を区別するために二相運動データを分析した.
主要な成果:
- M2チャネル活性化時に観察された二相運動学.
- 素早いHis37プロトネーション (2.0 × 10^10 M^-1 s^-1) を特定し,プロトン収集アンテナを示唆した.
- より遅い形状の変化を決定しました (4 × 10^3 s^-1),これは単純なトランスポーターではないことを示しています.
結論:
- M2チャネルの活性化には,異なるプロトネーションとコンフォメーションのステップが含まれます.
- 異常な速度のHis37陽子化は 効率的な陽子吸収メカニズムを示しています
- ゆっくりとした形状の変化は,M2チャネルが単純なトランスポーターモデルで動作しないことを示唆しています.
さらに関連する動画
12:15Single Liposome Measurements for the Study of Proton-Pumping Membrane Enzymes Using Electrochemistry and Fluorescent Microscopy
Published on: February 21, 2019
7.9K
09:54Multifunctional, Micropipette-based Method for Incorporation And Stimulation of Bacterial Mechanosensitive Ion Channels in Droplet Interface Bilayers
Published on: November 19, 2015
11.2K
関連する概念動画
ATP Synthase: Mechanism
18.0K
In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased...
18.0K
Mechanically-gated Ion Channels
7.9K
Mechanically-gated ion channels are proteins found in eukaryotic and prokaryotic cell membranes that open in response to mechanical stress. Tension, compression, swelling, and shear stress can alter the conformation of the protein, opening a transmembrane channel that allows the passage of ions for signal transmission. In eukaryotes, mechanically-gated channels are distributed in several regions like the neurons, lungs, skin, bladder, and heart, where they play critical roles in numerous...
7.9K
ATP Driven Pumps I: An Overview
10.1K
ATP-driven pumps, also known as transport ATPases, are integral membrane proteins. They have binding sites for ATP located on the membrane's cytosolic side and the ion-conducting domain in the transmembrane region. These pumps use the free energy released from ATP hydrolysis to move the solutes across cell membranes against an electrochemical gradient.
There are four main types of ATP-driven pumps - P-type, V-type, F-type, and ABC transporter. All these pumps are of varying complexities and...
There are four main types of ATP-driven pumps - P-type, V-type, F-type, and ABC transporter. All these pumps are of varying complexities and...
10.1K
Ligand-Gated Ion Channel Receptor: Gating Mechanism
4.4K
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...
4.4K
ATP Driven Pumps II: P-type Pumps
6.6K
The P-type pumps are a large family of integral membrane transporter ATPases. They are divided into five major types based on substrate specificity, from I to V.
A typical P-type pump has three cytosolic domains: nucleotide-binding (N), phosphorylation (P), and activator (A) domains. These domains are connected to the membrane-spanning helices by short amino acid segments. ATP hydrolysis and covalent phosphoenzyme intermediate formation are crucial parts of the catalytic cycle. At the highly...
A typical P-type pump has three cytosolic domains: nucleotide-binding (N), phosphorylation (P), and activator (A) domains. These domains are connected to the membrane-spanning helices by short amino acid segments. ATP hydrolysis and covalent phosphoenzyme intermediate formation are crucial parts of the catalytic cycle. At the highly...
6.6K
Energy to Drive Translocation
2.9K
Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Generally, polypeptides are unfolded by two distinct...
2.9K
