Na+,K(+) -ATPase 在 Na(+) 结合状态中的晶体结构
Maria Nyblom1, Hanne Poulsen, Pontus Gourdon
1Centre for Membrane Pumps in Cells and Disease-PUMPkin, Danish National Research Foundation, DK-8000 Aarhus, Denmark.
概括
研究人员揭示了-腺三酸酶 (Na(+),K(+) -ATPase) 在结合状态下的晶体结构. 这为酶的结构变化和离子结合部位提供了新的见解.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 分子生理学分子生理学
背景情况:
- 纳+),K+-腺三酸酶 (ATPase) 对于维持细胞电化学梯度至关重要.
- 之前的结构数据仅限于与结合的或ouabain受阻的状态.
研究的目的:
- 为了确定Na(+),K(+) -ATPase在与结合的结构中的晶体结构.
- 阐明参与酶功能的形状变化和离子结合位.
主要方法:
- 在4.3 Å分辨率的X射线晶体学.
- 分析Na(+) 结合形式和K(+) 结合形式之间的形状差异.
主要成果:
- 确定了与Na(+) 结合的Na(+),K(+) -ATPase的晶体结构.
- 在α子单元中观察到显著的构造变化,而β和γ子单元基本保持不变.
- 确定了三个Na(+) 结合点的位置,III点在IIIb位置得到确认.
- 电生理学研究支持了第三地点的拟定位置.
结论:
- 结合Na(+) 的结构揭示了Na(+),K(+) -ATPase的关键构造状态.
- 这些发现表明,细胞外Na(+) 释放和随后的K(+) 交换的机制.
- 这些结构信息有助于我们对离子运输和酶机制的理解.
更多相关视频
12:48Measuring Cation Transport by Na,K- and H,K-ATPase in Xenopus Oocytes by Atomic Absorption Spectrophotometry: An Alternative to Radioisotope Assays
Published on: February 19, 2013
10:39Visualization of ATP Synthase Dimers in Mitochondria by Electron Cryo-tomography
Published on: September 14, 2014
相关概念视频
ATP Synthase: Structure
ATP synthase or ATPase is among the most conserved proteins found in bacteria, mammals, and plants. This enzyme can catalyze a forward reaction in response to the electrochemical gradient, producing ATP from ADP and inorganic phosphate. ATP synthase can also work in a reverse direction by hydrolyzing ATP and generating an electrochemical gradient. Different forms of ATP synthases have evolved special features to meet the specific demands of the cell. Based on their specific feature, ATP...
ATP 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...
ATP 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...
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...
ATP 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...
