通过使用固态NMR光谱学检测的水蛋白相互作用检测到离子通道的形状变化
1Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
Journal of the American Chemical Society
|February 2, 2010
概括
流感A病毒M2蛋白质的质子通道水的可访问性随着pH和阿曼塔丁药物结合而变化. 固态NMR显示药物结合会脱水毛孔,影响病毒功能.
科学领域:
- 生物物理学的生物物理.
- 结构生物学 结构生物学
- 病毒学 病毒学
背景情况:
- 甲型流感病毒的M2蛋白形成了一个对病毒复制至关重要的质子通道.
- 了解M2蛋白与水的相互作用是其功能的关键,但直接证据有限.
研究的目的:
- 通过实验确定M2跨膜域 (M2-TM) 中的水的可访问性.
- 研究pH和阿曼塔丁结合等环境因素如何影响M2-TM水相互作用.
主要方法:
- 使用了 (1) H 旋转扩散固态NMR光谱.
- 分析了特定地点的水蛋白磁化转移和旋转扩散积累曲线.
- 采用3D格子模型模拟来量化水可访问的表面积.
主要成果:
- 孔内的残留物表现出高水的可访问性,受辐射位置的影响.
- 阿曼塔丁的结合显著降低了M2孔中的旋转扩散率,表明脱水.
- 在开放的低pH状态下,水的可访问性最高,在阿曼塔丁结合的高pH状态下最低.
结论:
- 提供了pH和阿曼塔丁诱导的M2孔径大小和水分的直接实验证据.
- 证明了 (1) H 旋转扩散 NMR 的实用性,用于研究膜蛋白中的水相互作用.
- 突出了与水可访问的表面积相关的M2蛋白质的构造变化.
相关概念视频
00:52¹H 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...
01:15¹H 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.