酸112是人类电压门式质子通道的选择性过器
Boris Musset1, Susan M E Smith, Sindhu Rajan
1Department of Molecular Biophysics & Physiology, Rush University Medical Center, Chicago, Illinois 60612, USA.
Nature
|October 25, 2011
概括
人类电压门式质子通道 (H(V) 1) 呈现出显著的质子选择性. 这项研究确定了阿斯巴酸盐112对HV1至关重要.
科学领域:
- 生物物理学的生物物理.
- 分子生物学分子生物学
- 离子通道功能的功能
背景情况:
- 和通道中的离子选择性对细胞功能至关重要.
- 人类的电压门式质子通道HV (HVCN1) 对质子非常有选择性.
- 在调节活性氧物种,胰岛素分泌,精子电容和呼吸道pH方面,H(V) 1的选择性至关重要.
研究的目的:
- 阐明 H ((V) 1.1.1 的非凡质子选择性背后的机制.
- 为了研究特定氨基酸残留在H(V) 1选择性过器中的作用.
主要方法:
- H(V) 1通道的局部定向突变发生,特别针对酸112和酸185.
- 突变通道的电生理学分析,以评估离子透性和选择性.
- 野生型与突变型HV1通道中的质子特异性的比较.
主要成果:
- 酸盐112 (Asp112) 转变为中性氨基酸导致质子特异性丧失,导致离子选择性或非导电性.
- 在位置112的谷氨酸突变保留了质子特异性.
- 阿斯巴酸盐185 (Asp185) 的突变没有影响质子选择性,突出了Asp112.2.的独特作用.
结论:
- 酸112是H(V) 1选择性过器的重要组成部分.
- 在选择性过器上需要一种酸性残留物,以获得H(V) 1的质子特异性.
- 这些发现挑战了基于histidine的质子穿机制对H(V) 1的选择性.
相关概念视频
Voltage-gated Ion Channels
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Voltage-gated Ion Channels
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Non-gated Ion Channels
Ion channels are specialized proteins on the plasma membrane that allow charged ions to pass down their electrochemical gradient. Their main function is to maintain the membrane potential which is critical for cell viability. These channels are either gated or non-gated and can transport more than a thousand ions within milliseconds for the cellular event to occur.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Non-gated Ion Channels
Ion channels are specialized proteins on the plasma membrane that allow charged ions to pass down their electrochemical gradient. Their main function is to maintain the membrane potential which is critical for cell viability. These channels are either gated or non-gated and can transport more than a thousand ions within milliseconds for the cellular event to occur.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Ligand-Gated Ion Channel Receptor: Gating Mechanism
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...


