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Recapitulation of an Ion Channel IV Curve Using Frequency Components
Published on: February 8, 2011
控制离子通道中Na(+) 与K(+) 选择性的因素
1Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan.
Journal of the American Chemical Society
|January 30, 2010
概括
这项研究揭示了影响 (Na+) 通道对 (K+) 通道选择性的关键因素. 通过特定的孔隙结构,连接体类型和离子水合状态来实现最佳的Na+选择性,从而提供了对道功能的洞察.
科学领域:
- 生物物理学的生物物理.
- 计算生物学 计算生物学
- 离子通道生理学 离子通道生理学
背景情况:
- 单价离子通道 (Na+和K+) 对于细胞功能至关重要,对它们的原生离子具有显著的选择性.
- 了解Na+与K+道中的Na+与K+选择性是具有挑战性的,因为结构数据有限,与K+道不同.
- 关于离子结合点和特定氨基酸替代对Na+/K+选择性的影响的关键问题仍然存在.
研究的目的:
- 在模型 Na+ 道选择性过器中系统地研究控制 Na+ 与 K+ 选择性的因素.
- 阐明孔隙协调组,离子水化和孔隙几何学在确定离子选择性的作用.
- 为了比较Na+和K+通道之间的选择性原则.
主要方法:
- 使用了密度函数理论 (DFT) 和连续介电方法的结合.
- 评估了不同孔隙连接体数,类型和电荷的影响.
- 评估了金属阴离子水化数,协调数和孔状特征 (溶剂暴露,刚性,收缩) 的影响.
主要成果:
- 通过:三种蛋白质连接体,强的电荷捐赠连接体 (例如,Asp/Glu碳酸盐),较少水合的Na+离子和刚性,狭窄的,暴露于溶剂的孔隙来增强Na+的选择性.
- 在Na+通道中促进Na+选择性的因素通常反对K+通道中的K+选择性.
- 确定了Na+和K+通道的独特选择性原则,与它们的过器架构相关联.
结论:
- 该研究提供了对控制离子通道中Na+与K+选择性的因素的系统评估.
- 这些发现提供了对表皮和电压接Na+通道选择性过器内的金属结合部位的结构洞察.
- 结果突出了Na+和K+通道中离子选择性的不同进化策略.
相关概念视频
The Role of Ion Channels in Neuronal Computation
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
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...
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.
Resting Potential Decay
The resting membrane potential of a neuron (-70mV) is sustained due to the selective ion permeability of the membrane. At the resting potential, the membrane is slightly permeable to ions like sodium (Na+) and chloride (Cl−) and highly permeable to potassium ions (K+). Differences in the ions' concentration inside the cell compared to the outside are maintained by membrane transport proteins like channels and pumps.
At rest, the K+ is the main ion that moves across the membrane through...
At rest, the K+ is the main ion that moves across the membrane through...

