在阿尔法螺旋展开中,从激光T跳/紫外线拉曼光谱学中,体和体阶段
Gurusamy Balakrishnan1, Ying Hu, Gretchen M Bender
1Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
Journal of the American Chemical Society
|October 4, 2007
概括
我们使用紫外线共振拉曼光谱研究了蛋白质α螺旋的展开动态. 我们的研究结果揭示了螺旋融化的独特的旋和热阶段,这取决于温度跳跃条件.
科学领域:
- 生物物理学的生物物理.
- 蛋白质动力学 蛋白质动力学
- 频谱学是一种光谱学.
背景情况:
- 阿尔法螺旋是重要的蛋白质结构,但它们的温度依赖的展开机制尚未完全理解.
- 之前的研究缺乏详细的洞察力螺旋融的动力学.
研究的目的:
- 为了研究在稳定中展开的α螺旋体的温度依赖动态.
- 应用一种新的激光系统,用于对蛋白质构造变化的时间解析光谱分析.
主要方法:
- 使用kHz重复率的固态调节NIR和深紫外线拉曼激光系统.
- 采用197nm激发紫外线共振拉曼光谱 (UVRR) 来增强胺振动.
- 分析了T-依赖的UVRR光谱,并进行了激光诱导的T跳.
主要成果:
- 在低温下,UVRR和循环二重化 (CD) 显示出一致的螺旋分数,在高温下分歧.
- 激光诱导的T跳转揭示了单指数螺旋展开的~120 ns的衰变,独立于最终温度.
- 确定了螺旋性的快速丧失 (内旋阶段),随后是较慢的阶段 (内热阶段).
结论:
- 与CD相比,UVRR对局部蛋白质构成更为敏感.
- 螺旋体展开涉及明显的 (H键破坏) 和 (链重定位) 阶段.
- 观察到的动态受到T跳跃期间的初始和最终温度的影响.
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