相关实验视频
Updated: Jul 5, 2026

06:48
CD Spectroscopy to Study DNA-Protein Interactions
Published on: February 10, 2022
固态核磁共振光谱学研究了DNAHhaI结合点中的 furanose环动态
Gary A Meints1, Paul A Miller, Kari Pederson
1Department of Chemistry, Missouri State University, Springfield, Missouri 65897, and Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA.
Journal of the American Chemical Society
|May 21, 2008
概括
固态NMR显示,GCGC DNA序列中的 furanose 环是灵活的. 甲基化会影响这些动态,影响DNA与HHAI甲基转移酶等酶的相互作用.
科学领域:
- 分子生物物理学 分子生物物理学
- 核磁共振光谱学 核磁共振光谱学
- 基因动力学 基因动力学
背景情况:
- DNA结构和动态对于分子识别和酶过程至关重要.
- GCGC序列是DNA中的一个关键动机,经常参与蛋白质结合和甲基化.
- 了解 furanose 环的灵活性对于阐明 DNA 的结构变化至关重要.
研究的目的:
- 为了研究特定DNA寡合体GCGC部分内的 furanose环的结构动态.
- 为了确定甲基化如何影响这些 furanose 环的灵活性.
- 为了将DNA动态与酶结合相关联,特别是HhaI甲基转移酶.
主要方法:
- 使用了固态核磁共振 (SSNMR) 光谱学.
- 在5'-GCGC-3'序列内进行了 furanose 环的选择性化.
- 核磁共振线形状的分析,以量化酸环运动和的振幅.
主要成果:
- 在5'-GCGC-3'部分内,所有研究的黄环位置都表现出显著的结构灵活性.
- 甲基化的目标,即脱氧化丁 furanose 环,显示出最大幅度的结构变化.
- 远离甲基化部位的 furanose 环表现出减少的移动性 (puckering 幅度 < 0.3 Å).
- 观察到甲基化通过 furanose 环扰乱骨干动力学.
结论:
- DNA中的5'-GCGC-3'部分本质上是动态的,其运动集中在甲基化位点附近.
- 这种固有的灵活性促进了DNA与甲基转移酶 (如HHAI) 结合所需的大幅度结构重组.
- furanose环动态中的甲基化诱导的变化在调节 DNA-蛋白相互作用方面发挥着作用.
相关概念视频
Other Nuclides: 31P, 19F, 15N NMR
Many organic, inorganic, and biological molecules contain spin-half nuclei such as nitrogen-15, fluorine-19, and phosphorus-31. As a result, NMR studies of these nuclei have found extensive applications in chemical and biological research.
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a high...
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a high...
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...
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...
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.
2D NMR: Heteronuclear Single-Quantum Correlation Spectroscopy (HSQC)
Heteronuclear single-quantum correlation spectroscopy (HSQC) is a 2D NMR technique that reveals one-bond correlations between hydrogen and a heteronucleus. The HSQC experiment is similar to the heteronuclear correlation experiment (HETCOR) but is more sensitive. In the HSQC spectrum, the proton chemical shift is plotted on the horizontal F2 axis, while the 13C chemical shift is plotted on the vertical F1 axis. The corresponding proton and 13C spectra are also shown. The HSQC contour plot does...
Atomic Nuclei: Magnetic Resonance
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...

