直接观察蛋白质的毫秒到秒运动,使用二极CODEX NMR光谱学
Alexey Krushelnitsky1, Eduardo deAzevedo, Rasmus Linser
1Kazan Institute of Biochemistry and Biophysics, Kazan, Russia. krushelnitsky@mail.knc.ru
Journal of the American Chemical Society
|August 14, 2009
概括
这项研究使用了经过修改的NMR技术来分析微晶体中蛋白质的缓慢运动. 研究人员观察到SH3蛋白质域中的毫秒到秒的时间尺度动态和分子重定位.
科学领域:
- 生物物理学的生物物理.
- 结构生物学 结构生物学
- 核磁共振 (NMR) 光谱学 核磁共振 (NMR) 光谱学
背景情况:
- 了解蛋白质动态对于阐明生物功能至关重要.
- 固态NMR是研究蛋白质结构和动态的强大工具.
- 之前的方法缺乏蛋白质中缓慢运动 (ms到s) 的特定位点分辨率.
研究的目的:
- 开发和应用一个修改的NMR实验,用于缓慢的蛋白质运动的现场解析分析.
- 研究SH3蛋白域内内部动态的时间尺度和几何.
- 为了提高灵敏度,并最大限度地减少蛋白质动态的固态NMR研究的文物.
主要方法:
- 使用了一个修改的中带仅检测交换 (CODEX) 的NMR实验.
- 专注于内核载体的角度重定向,而不是通过CSA张量进行分子定向.
- 采用半化SH3域与部分质子反交换,以增强间接的 (15) N检测.
主要成果:
- 在微晶SH3蛋白域中观察到位点解析的缓慢运动 (ms到s).
- 大约50%的光谱峰显示不同程度的交换,表明动态过程.
- 确定慢动作相关时间,主要在1-3秒范围内.
结论:
- 经过修改的CODEX NMR方法为固态中缓慢的蛋白质动态提供了前所未有的特定位置的洞察力.
- 这项研究为在毫秒到秒的时间尺度上描述蛋白质运动的时间尺度和几何学建立了新的能力.
- 这些发现有助于更深入地了解蛋白质灵活性及其在生物机制中的作用.
相关概念视频
2D NMR: Overview of Homonuclear Correlation Techniques
Homonuclear correlation spectroscopy (COSY) is a powerful technique used in Nuclear Magnetic Resonance (NMR) spectroscopy to study the correlations between nuclei of the same type within a molecule. It provides information about scalar couplings between adjacent nuclei, which helps determine connectivity and structural information. There are several COSY variants, each with its unique strengths and experimental parameters.
COSY90 is the standard two-dimensional (2D) COSY experiment that...
COSY90 is the standard two-dimensional (2D) COSY experiment that...
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
Double Resonance Techniques: Overview
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
Protein Dynamics in Living Cells
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Two-Dimensional (2D) NMR: Overview
The 1D NMR spectrum of large and complex molecules like natural products has complicated splitting patterns and overlapping signals, which can be easily interpreted using 2-dimensional (2D) NMR. Unlike 1D NMR, 2D NMR has two frequency axes that provide the coupling information between the nucleus A and nucleus B in a molecule. The process from which 2D spectra are obtained has four steps.
The first step is the preparation period, during which nucleus A is excited with a radiofrequency pulse.
The first step is the preparation period, during which nucleus A is excited with a radiofrequency pulse.
¹H NMR: Interpreting Distorted and Overlapping Signals
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...

