在CaiT的Na(+) 独立和合作基质/产品反端口的结构基础
Sabrina Schulze1, Stefan Köster, Ulrike Geldmacher
1Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt am Main, Germany.
Nature
|September 11, 2010
概括
研究人员确定了与无关的卡尼丁/丁抗载体CaiT的结构,揭示了在不依赖离子的情况下通过膜传输溶解物的一种新型机制.
科学领域:
- 结构生物学是结构生物学.
- 膜运输是通过膜运输来实现的.
- 生物化学 生物化学
背景情况:
- 生物膜运输对生命至关重要,通常由二次传送器介导.
- 贝他因/卡尼丁/胆载体 (BCCT) 通常依赖于 (Na+) 或质子 (H+).
- CaiT的独立性质在BCCT家族中是一个独特的案例.
研究的目的:
- 为了阐明不依赖的卡尼丁/丁罗贝抗载体 (CaiT) 功能的结构基础.
- 了解在没有Na+或H+依赖的情况下溶解物运输的机制.
- 描述CaiT的功能状态和基质结合.
主要方法:
- 使用X射线晶体学来确定来自Proteus mirabilis (PmCaiT) 和大肠杆菌 (EcCaiT) 的CaiT的结构.
- 在功能性研究中,将CaiT复制成蛋白质体进行了.
- 进行了约束性测定和基质合作性的分析.
主要成果:
- PmCaiT (2.3-A) 和EcCaiT (3.5-A) 的结构显示出一个面向内部的形状.
- 一个氨酸硫原子,而不是一个Na+离子,协调了CaiT.的运输位点中的基质.
- EcCaiT显示了两个结合的布罗贝分子,一个在运输部位,一个在细胞外口袋中,表明了合作结合.
结论:
- CaiT使用了一种新的不依赖的运输机制,涉及 metionin 的协调.
- CaiT结构提供了交替访问机制的完整图景.
- 合作基质结合,细胞外部作为调节部位,提高运输效率.
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相关概念视频
Active Transport
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Primary active transporters, like Na+, K+ and -ATPase, directly utilize ATP to move ions across the membrane. These transporters play significant roles in various physiological processes. For instance, Na+, K+ and -ATPase maintain...
Primary active transporters, like Na+, K+ and -ATPase, directly utilize ATP to move ions across the membrane. These transporters play significant roles in various physiological processes. For instance, Na+, K+ and -ATPase maintain...
Secondary 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...
Secondary 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...
Secondary 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...
Primary 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...
Primary 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...
