过渡性紫外线拉曼光谱法没有发现体α螺旋和完全随机的线圈形状之间的交叉屏障
I K Lednev1, A S Karnoup, M C Sparrow
1Contribution from the Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
Journal of the American Chemical Society
|July 18, 2001
概括
这项研究使用紫外线共振拉曼光谱法确定了酸中的最终α螺旋转的快速展开速度. 发现的展开速度大于5 x 10^6 s^-1.
科学领域:
- 生物物理学的生物物理.
- 化学物理 化学物理
- 频谱学是一种光谱学方法.
背景情况:
- 了解的折叠和展开动态对于蛋白质结构-功能关系至关重要.
- 螺旋展开的最后阶段没有得到很好的描述.
- 阿尔法螺旋可以作为研究蛋白质动态的模型系统.
研究的目的:
- 为了确定模型的终端α-螺旋旋转的展开速度.
- 为了研究温度跃升后形变化的动力学.
- 为了为螺旋体展开速度提供下限.
主要方法:
- 使用过渡性紫外线共振拉曼光谱.
- 采用了3ns的温度跳跃,由1.9微米激光脉冲被水吸收.
- 通过使用204nm紫外线脉冲,在各种延迟时间 (3ns到1ms) 中通过胺基拉曼光谱监测形演变.
主要成果:
- 观察到的放松时间大约为180 ns.
- 计算出一个速度常数大于5 x 10^6 s^-1的最后一个alpha螺旋转的展开.
- 展开的过程导致一个完全随机的线圈.
结论:
- 最终的α螺旋转迅速展开,速度常数超过5 x 10^6 s^-1.
- 观察到的快速展开的动力学与涉及缓慢的α螺旋核融的模型不一致.
- 这项研究为终端螺旋旋转的展开速度提供了第一个实验下限.
相关概念视频
UV–Vis Spectrum
When light passes through a substance, a portion of the light is absorbed while the remaining light is reflected or transmitted. If the molecule absorbs light between the wavelengths of 180–400 nm range, the UV spectrum is obtained, and if it absorbs light in the 400–780 nm wavelength range, the visible spectrum is obtained.
The UV–Vis spectrum of a molecule is the plot of its absorbance versus wavelength. The plot is drawn by taking molar absorptivity (ε) or log ε on the y-axis (ordinate)...
The UV–Vis spectrum of a molecule is the plot of its absorbance versus wavelength. The plot is drawn by taking molar absorptivity (ε) or log ε on the y-axis (ordinate)...
UV–Vis Spectroscopy: Molecular Electronic Transitions
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this process,...


