细胞分解性α-螺旋式毒素孔的结构揭示了其组装机制
Marcus Mueller1, Ulla Grauschopf, Timm Maier
1Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.
Nature
|May 8, 2009
概括
形成毛孔的毒素 (PFTs) 经历了显著的结构变化,形成了膜毛孔. 这项研究揭示了α-螺旋式Cytolysin A (ClyA) 孔的详细结构,揭示了孔形成的顺序机制.
科学领域:
- 微生物学 微生物学
- 结构生物学 结构生物学
- 毒理学 毒理学 毒理学
背景情况:
- 形成毛孔的毒素 (PFTs) 是关键的毒性因子,从可溶性形式过渡到膜毛孔,导致细胞损伤或输送毒素.
- 根据它们的膜融合机制,PFTs被分类为α-PFTs或β-PFTs.
- 细胞素A (ClyA) 是来自大肠杆菌等细菌的α-PFT,具有细胞毒性,促进组织入侵.
研究的目的:
- 确定由Cytolysin A (ClyA) 形成的跨膜孔的高分辨率结构.
- 为了阐明ClyA孔隙形成所涉及的构造变化,从其可溶性单体状态.
主要方法:
- 采用X射线晶体学,确定了十二角形ClyA孔的3.3 Å结构.
- 通过将孔隙结构与可溶性ClyA单体的已知结构进行比较,分析了形状变化.
主要成果:
- 确定了ClyA的400kDa的十二角形跨膜孔结构.
- 与可溶性单体相比,孔中的ClyA原体表现出明显改变的三级结构,涉及所有残留物的一半以上.
- 显著的构造变化包括大规模的重排,疏水性核心重组,以及从β-sheet/loops到alpha-helices的过渡.
结论:
- 在ClyA孔隙结构揭示了孔隙形成过程中广泛的,相互依存的形状变化.
- 这些发现表明,ClyA.的膜插入和毛孔组装有序机制.
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