プラズマ膜H+-ATPASEの3次元地図は,開いた形状で作成されています
M Auer1, G A Scarborough, W Kühlbrandt
1Max-Planck-Institut für Biophysik, Abteilung Strukturbiologie, Frankfurt am Main, Germany.
Nature
|May 8, 1998
まとめ
研究者は電子結晶学を用いて,重要な陽子ポンプであるNeurospora crassa H+-ATPaseを視覚化しました. これは,細胞膜ポテンシャルを維持するP型ATPアザの構造と機能に関する新しい洞察を提供します.
科学分野:
- 構造生物学 構造生物学とは
- バイオケミストリー バイオケミストリー
- 分子生物物理学 分子生物物理学
背景:
- H+-ATPaseを含むP型ATPaseは,膜ポテンシャルとイオン濃度の調節に不可欠である.
- これらのタンパク質におけるイオン輸送の分子機構の理解は,構造的な課題のために制限されています.
- Neurospora crassaのプラズマ膜からのH+-ATPaseは100Kの統合膜タンパク質である.
研究 の 目的:
- H+-ATPASEの3次元構造を決定する.
- 陽子輸送の分子メカニズムを解明する.
- 大型の膜タンパク質の結晶化における限界を克服するために.
主な方法:
- H+-ATPASEの二次元結晶の電子結晶学.
- 電子顕微鏡のグリッドに直接結晶の成長.
- 平面内解像度8 Åの3Dマップの生成. 平面内解像度8 Åの3Dマップの生成. 平面内解像度8 Åの3Dマップの生成. 平面内解像度8 Åの3Dマップの生成. 平面内解像度8 Åの3Dマップの生成.
主要な成果:
- H+-ATPaseの3Dマップが得られた.
- 地図は,膜領域の10つの膜を横断するアルファヘリクスを示しています.
- 酵素のオープンコンフォーメーションで4つの主要なサイトプラズミックドメインが特定されました.
結論:
- この研究は,H+-ATPase.への最初の詳細な3D構造の洞察を提供します.
- この発見は,P型ATPアゼのイオン輸送機構を理解するための基礎を提供している.
- 電子結晶学は,複雑な膜タンパク質の構造を決定するための有効な方法である.
関連する概念動画
01:19Fluid Mosaic Model
Scientists identified the plasma membrane in the 1890s and its principal chemical components (lipids and proteins) by 1915. The model for plasma membrane structure, proposed in 1935 by Hugh Davson and James Danielli, was the first model to be widely accepted in the scientific community. The model was based on the plasma membrane's "railroad track" appearance in early electron micrographs. Davson and Danielli theorized that the plasma membrane's structure resembled a sandwich with the analogy of...
01:25Single-pass Transmembrane Proteins
Integral membrane proteins are tightly associated with the cell membrane and play a crucial role in cell communication, signaling, adhesion, and transport of the molecules. Some integral membrane proteins are present only in the membrane monolayer. For example, the enzyme fatty acid amide hydrolase is present in the cytoplasmic side of the membrane monolayer. In contrast, another type of integral membrane protein, also known as a transmembrane protein, spans across the membrane. Transmembrane...
01:48ATP Synthase: Mechanism
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 ATP...
01:34ATP Driven Pumps II: P-type Pumps
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...
01:30ATP Driven Pumps III: V-type Pumps
V-type pumps are ATP-driven pumps found in the vacuolar membranes of plants, yeast, endosomal and lysosomal membranes of animal cells, plasma membranes of a few specialized eukaryotic cells, and some prokaryotes. They are also known as the V1Vo-ATPase, that couple ATP hydrolysis to transport protons against a concentration gradient.
The peripheral or cytosolic V1 domain with eight subunits is involved in ATP hydrolysis. The integral or transmembrane V0 domain containing at least five subunits...
The peripheral or cytosolic V1 domain with eight subunits is involved in ATP hydrolysis. The integral or transmembrane V0 domain containing at least five subunits...
01:19Membrane Asymmetry Regulating Transporters
Enzymes like flippase, floppase, and scramblase transfer phospholipids from one layer to another in the membrane, thereby affecting membrane asymmetry.
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...