カルシウムポンプによるカルシウム輸送の構造的基礎
Claus Olesen1, Martin Picard, Anne-Marie Lund Winther
1Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, University of Aarhus, Ole Worms Alle, blg. 1185, DK - 8000 Aarhus C, Denmark.
Nature
|December 14, 2007
まとめ
サルコプラズマ網膜のCa2+-ATPase結晶構造は,カルシウム輸送のためのメカニズムを明らかにします. このP型ATPアゼは,筋肉の機能と細胞のエネルギーに重要な役割を果たします.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- 構造生物学 構造生物学とは
背景:
- サルコプラズマの網膜にあるCa2+-ATPase (SERCA) は,P型ATPaseである.
- 筋肉の収縮と細胞カルシウムホメオスタシスを調節する.
- その輸送メカニズムを理解することは,細胞の機能に不可欠です.
研究 の 目的:
- ウサギの骨格筋のCa2+-ATPaseの機能的メカニズムを解明する.
- カルシウム結合,転位,脱リン酸化に関する構造的な洞察を提供するため.
- ヌクレオチド結合とカチオン輸送のサイクルを完了するために.
主な方法:
- Ca2+-ATPaseの機能に関する研究.
- 3つの異なる結晶構造を決定するX線結晶学.
- ATPアナログ,ベリリウムフッ素,アルミニウムフッ素で形成された複合体.
主要な成果:
- 3つの結晶構造は,重要なフォスフォエンザイム中間物質を表しています.
- 酸化は形状の変化を誘発し,光の経路を開く.
- M4ヘリクスのトランスロケーションにより,Ca2+がルメンに放出されやすくなります.
結論:
- 構造は,Ca2+-ATPアゼ輸送サイクルを総合的に見ることができます.
- このメカニズムは,P型ATPアゼが電気化学的グラデーションをどのように確立するかを説明する.
- この研究は,基本的な細胞のプロセスについての理解を深める.
関連する概念動画
01:47Primary Active Transport
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps that are embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they...
01:29Primary Active Transport
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they would not...
01:32Secondary Active Transport
One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme "pump" embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
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...
01:27Feedback Regulation of Calcium Concentration
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
01:29Primary Active Transport
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they would not...