对bacteriorhodopsin的交换质谱检测揭示了生物分子机器结构动态的光诱导变化
Yan Pan1, Leonid Brown, Lars Konermann
1Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7.
Journal of the American Chemical Society
|November 3, 2011
概括
像bacteriorhodopsin这样的分子机器,当它们的循环运动活跃时,会呈现出更大的热波动. 通过/交换质谱仪监测的光驱动蛋白质动力学,揭示了光诱导的不稳定性和增强的波动.
科学领域:
- 生物物理学的生物物理.
- 结构生物学 结构生物学
- 蛋白质动力学 蛋白质动力学
背景情况:
- 蛋白质作为分子机器,利用非热能来源进行循环运动 (CM).
- 热波动 (TFs) 叠加在CMs上,并与溶剂随机性相结合.
- 轻量驱动的质子Bacteriorhodopsin (BR) 作为研究CMs和TFs之间的相互作用的模型.
研究的目的:
- 调查分子机器中的TF是否受到CMs的发生的影响.
- 探索光驱动的循环运动对背后的热波动的影响.
- 利用/交换 (HDX) 质谱测量来探测不同功能状态下的蛋白质动态.
主要方法:
- /交换 (HDX) 质谱法被用来监测单体巴克特里奥多普辛中的TF.
- 在照明下 (发动机打开) 和在黑暗中 (发动机关闭) 进行了HDX比较研究.
- 使用无视网膜蛋白进行了对照实验,以隔离依赖光的效应.
主要成果:
- 在照明下,BR的HDX动力学显著加快,同位素交换率和参与的骨干胺基大约增加了2倍.
- 光引起的HDX行为差异归因于蛋白质不稳定,照明使热力学稳定性减少2.2kJmol{-1}.
- 视网膜自由蛋白质对照没有显示明显的光/黑暗差异,证实了光驱动光循环的作用.
结论:
- 在bacteriorhodopsin中的热波动的程度强烈依赖于光子驱动的循环运动.
- 光引起的视网膜运动作为内部能量来源,通过机械动和随后的能量消耗促进TFs.
- HDX方法是有效的探测分子机器的结构动力学在活跃和非活跃状态.
相关概念视频
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Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
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Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...