通过神奇角度旋转的NMR研究重组的硫素的动力学:来自不同时间尺度的快照
Jun Yang1, Maria Luisa Tasayco, Tatyana Polenova
1Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
Journal of the American Chemical Society
|September 10, 2009
概括
固态核磁共振显示了在没有分子翻转的情况下,硫素中的蛋白质动态. 它显示不规则结构中的移动性高于alpha-helices或beta-sheets中的移动性,在不同的时间尺度上对应运动.
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:
- 固态NMR光谱是研究蛋白质动态的一个强大的工具.
- 蛋白质的内部运动可以独立于整体分子翻转而被调查.
- 硫素是一种关键的蛋白质,参与氧化还原调节.
研究的目的:
- 通过使用固态NMR在多个时间尺度上研究重组的 thioredoxin 的骨干动力学.
- 在不同的时间尺度上发生的运动相对应,并将它们与溶液NMR和晶体学数据进行比较.
- 了解蛋白质结构和内部动态之间的关系.
主要方法:
- 使用了差异丰富的重新组装的硫素 (1-73 ((U- ((13) C, ((15) N) /74-108 ((U- ((15) N)).
- 采用了一系列2D和3D魔力角旋转 (MAS) NMR实验.
- 探测了脊柱胺基 (15) N 纵向放松, (1) H-(15) N 双极顺序参数, (15) N 化学转移异构性 (CSA) 和信号强度.
主要成果:
- 观察到站点对站点的动力学显著变化 (比秒到纳秒的时间尺度),旋转放松率R ((1) 从0.012到0.64s ((-1) 之间.
- 确定平均值 (1)H-(15)N双极顺序参数
= 0.89 ± 0.06 和 (15)N CSA 异构三角形 ((sigma) = 92.3 ± 5.2 ppm. - 与α-螺旋体和β-片相比,在不规则的二次结构的残留物中发现了更高的流动性,固态和溶液NMR顺序参数之间的趋势相似.
结论:
- 固态NMR提供了对蛋白质动态和运动在多个时间尺度上的相关性的洞察.
- 内部动力学受到二次结构元素的影响,不规则结构具有更大的灵活性.
- 与晶体学B因子进行比较,可以区分静态混乱和内部运动的贡献.
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