由BAM复合体插入外膜蛋白的结构基础
Yinghong Gu1, Huanyu Li1, Haohao Dong1
1Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
Nature
|February 23, 2016
概括
细菌外膜蛋白组装机制 (BAM) 现在更加清晰. 结构研究揭示了Bama和相关蛋白质如何旋转,将新的外膜蛋白 (OMP) 插入细胞外.
科学领域:
- 结构生物学
- 分子生物学
- 生物化学
背景情况:
- 外膜蛋白 (OMP) 对于格拉姆阴性细菌,线粒体和叶绿体至关重要.
- 该β-桶组装机械 (BAM) 复合体有助于将OMP插入和折叠到外膜.
- 由于缺乏结构数据,BAM介导的OMP生物发生的确切机制仍然在很大程度上是未知的.
研究的目的:
- 阐明BAM复合体对外膜蛋白的插入机制.
- 为大肠杆菌BAM复合体提供高分辨率的结构洞察力.
- 了解OMP生物生成过程中BAM子单元之间的动态相互作用.
主要方法:
- 用X射线结晶学来确定不同状态的BAM复合物的结构.
- 生物化学测定用于研究BAM复合元件的功能.
- 分子动力学模拟分析BAM复合体内的动态运动.
主要成果:
- 确定了大肠杆菌BAM复合体的两个不同的晶体结构:向内开放状态和侧向开放状态.
- 这些结构显示了由BamA的五个多运输相关域形成的环结构,与四个脂蛋白 (BamB-BamE) 相关.
- 结构和功能数据表明,相对于BamA的β桶,相关脂蛋白的旋转驱动了新生OMP的插入.
结论:
- 这项研究为BAM复合体提供了前所未有的结构快照,
- 这些发现阐明了由BAM复合物介导的基于轮换的OMP插入机制.
- 这项工作显著提升了我们对基本膜蛋白的生物发生过程的理解.
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