柱的循环和柱生物发生是无序的,但静电扰动会损害结合效率
Shan He1, Naito Ishimoto1,2,3, Joshua L C Wong1
1Department of Life Sciences, Imperial College London, London, UK.
Nature communications
|February 18, 2026
概括
细菌的结合依赖于柱子循环. 在TrhA柱体中的特定氨基酸替代物通过改变柱体表面电荷和硬质性质来影响DNA转移效率,突出了有效的等离子体转移的进化约束.
科学领域:
- 微生物学 微生物学
- 分子生物学分子生物学
- 结构生物学 结构生物学
背景情况:
- 细菌结合促进了通过等离子体DNA传播的水平基因转移.
- 由子子单元组成的交配柱 (pilus) 在这个过程中至关重要.
- 在IncHI1 R27等离子体中TrhA皮林的循环转化对于结合至关重要.
研究的目的:
- 研究TrhA在Gly1和Asp69中的平林循环化在细菌结合中的作用.
- 确定Asp69中的替代如何影响柱状结构,功能和结合效率.
- 阐明在结合过程中控制柱体-受体相互作用的静电和静电因素.
主要方法:
- 在Gly1和Asp69.9的TrhA皮林的局部定向突变发生.
- 使用电子显微镜 (隐含) 分析柱状形成和结构.
- 对不同细菌受体菌株的结合效率的评估,包括那些外膜成分改变的细菌菌株.
主要成果:
- 在Asp69的TrhA柱子循环不严格要求柱子形成.
- 用较小的侧链 (Asn,Ala,Gly) 在Asp69上的替代物保持了对效率,与侧链大小相关.
- 用充电或体积大的残留物 (Arg,Lys) 取消结合的替代物,与改变的柱体表面电荷和与受体膜的静电相互作用有关.
- 在缺乏酸乙醇胺 (PE) 的接受者中,挽救了结合,证实了静电相互作用的作用.
结论:
- 保存的Gly1和Asp69残留物受到强大的选择性压力,以保持高效的DNA转移.
- 柱体表面的精确静电和静电性质对于成功的细菌结合至关重要.
- 通过特定的氨基酸替代来调节柱体表面电荷可以取消或拯救结合,这取决于受体膜组成.
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