在K+离子通道的选择性过器内部的水:结构异质性,皮秒动态和结合
Matthew J Ryan1, Lujia Gao2, Francis I Valiyaveetil2
1Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
bioRxiv : the preprint server for biology
|November 28, 2023
概括
生物离子通道内的水动力学至关重要. 这项研究揭示了KcsA通道内的水分子表现出缓慢的重定向,与高度动态的液态水不同,离子和蛋白质在皮秒时间尺度上保持静态.
科学领域:
- 生物物理学的生物物理.
- 物理化学 物理化学
- 分子生物学分子生物学
背景情况:
- 水在生物离子通道功能中的作用对于选择性,离子导电性和门性至关重要.
- 了解道内的分子水平的水动力学,可以了解蛋白质的功能.
研究的目的:
- 为了阐明KcsA道的选择性过器内水和离子的特定位置动态.
- 为了研究在同位素标记KcsA通道中的胺I振动的皮秒光谱扩散.
主要方法:
- 在同位素标记的KcsA通道 (Val76和Gly77残留物) 上使用二维红外 (2D IR) 光谱学.
- 进行分子动力学模拟以补充实验数据.
- 分析了依赖于等待时间 (100-2000 fs) 的二维内射测量.
主要成果:
- 观察到不均的二维线形与极其缓慢的光谱扩散.
- 模拟对实验结果进行了定量复制,表明水具有动态,而离子和蛋白质在皮秒时间尺度上是静态的.
- 确定了与碳基组形成键的独特水方向,具有不同的重定向时间,其中一些表现为"自由"气相水.
结论:
- 在KcsA选择性过器中,水的动态明显比散装液体水慢得多.
- 在皮秒时间尺度上,没有观察到不同水配置之间的相互转换.
- 这些发现凸显了离子通道内水的受约束和独特的动态,影响了通道功能.
更多相关视频
11:55Examining the Conformational Dynamics of Membrane Proteins in situ with Site-directed Fluorescence Labeling
Published on: May 29, 2011
15.1K
08:54Monitoring Leucine-Rich Repeat Containing 8 Channel (LRRC8/VRAC) Activity Using Sensitized-Emission Förster Resonance Energy Transfer (SE-FRET)
Published on: August 9, 2024
454
相关概念视频
Aquaporins
4.9K
Aquaporins or AQPs are a family of integral membrane proteins whose primary function is to transport water, while some called aquaglyceroporins also transport glycerol. In addition, aquaporins have also been suspected to be involved in transporting volatile substances, such as carbon dioxide and ammonia, across membranes. Such AQPs that act as gas channels are often highly expressed in cells involved in the gaseous exchange, such as red blood cells, epithelial cells, and pulmonary capillaries.
4.9K
Electrochemical Gradient and Channel Proteins: An Overview
2.3K
An electrochemical gradient is a fundamental concept in biology and chemistry. It regulates the movement of ions across cell membranes. This movement is influenced by two factors:
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to...
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to...
2.3K
The Role of Ion Channels in Neuronal Computation
3.2K
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....
3.2K
Voltage-gated Ion Channels
8.3K
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...
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...
8.3K
Ligand Binding Sites
12.9K
Proteins are dynamic macromolecules that carry out a wide variety of essential processes; however, the activities of most proteins depend on their interactions with other molecules or ions, known as ligands.
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
12.9K
Non-gated Ion Channels
6.8K
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....
6.8K
