分子拥挤稳定了固有无序的无状态和重复在毒素 (RTX) 蛋白质的折叠结合状态
Ana-Cristina Sotomayor-Pérez1, Orso Subrini, Audrey Hessel
1Unité de Biochimie des Interactions Macromoléculaires, CNRS UMR 3528, Département de Biologie Structurale et Chimie, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris cedex 15, France.
Journal of the American Chemical Society
|August 15, 2013
概括
大分子拥挤增强了RTX蛋白的结合和稳定性,如RC(L). 这种在无序 (apo) 和折叠 (holo) 状态中观察到的效应表明,拥挤会影响蛋白质的输出和细胞内的功能.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
背景情况:
- 宏分子拥挤,即高度宏分子的存在,在细胞中限制了可用的空间.
- 这种现象显著影响化学平衡和生物过程.
- RTX (重复在毒素) 图案是结合序列,在细菌毒性因子中至关重要.
研究的目的:
- 调查宏分子拥挤对RTX蛋白RC的折叠和结合的影响.
- 在本质上无序 (apo) 和结合 (holo) 状态中对单个多链进行拥挤效应的特征.
- 了解拥挤对RTX蛋白功能和分泌的影响.
主要方法:
- 使用Ficoll70作为拥挤剂来模仿细胞条件.
- 在不同拥挤条件下评估RC的蛋白质结构含量和亲和力.
- 在Ficoll70.0.L的存在下测量了RC的热稳定性 (化温度) 和度变化.
- 分析了融化温度增加和拥挤体积分数之间的关系,以估计弗洛里指数.
主要成果:
- 在apo或Holo状态下,Ficoll70没有改变RC的结构含量.
- 拥挤显著增加了RC (L) 对的亲和力.
- 在Ficoll70.L的存在下,RC(L的apo和Holo状态都表现出增强的热稳定性.
- 融化温度的增加遵循理论预测,允许估计未折叠RC的Flory指数.
结论:
- 大分子拥挤增强结合,稳定RTX蛋白在无序和折叠状态.
- 在拥挤的细胞质中,RTX蛋白可能会采用扩展的构造,促进出口.
- 拥挤还可以促进RTX蛋白在细胞外环境中的依赖的折叠和稳定性.
- 这些发现强调了细胞拥挤在调节蛋白质结构,功能和分泌中的关键作用.
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