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, Joshua L C Wong1
1Department of Life Sciences, Imperial College London, SW7 2AZ, UK.
bioRxiv : the preprint server for biology
|December 3, 2025
概括
细菌的结合依赖于一个柱状结构. 柱体表面的特定氨基酸Gly1和Asp69对于DNA转移效率至关重要,电荷和大小影响相互作用.
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:
- 细菌的结合促进了通过等离子体编码的交配 pili.通过水平基因转移.
- 这种IncHI1 R27等离子体pilus是由聚合的TrhApilin子单元组成的.
- 在Gly1和Asp69之间进行的TrhA轮循环对于结合至关重要.
研究的目的:
- 调查Gly1和Asp69在TrhA柱体结构和功能中的作用.
- 确定Asp69中的替代物如何影响柱状形成和结合效率.
- 阐明控制柱介导DNA转移的静电和静电约束.
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.
- 对不同受体菌株的细菌结合效率的评估,包括那些具有修饰外膜的细菌.
主要成果:
- Asp69的替代物 (Asn,Ala,Gly) 没有阻止柱状组织的形成或循环.
- 结合效率与Asp69侧链的大小相关 (Asn > Ala > Gly).
- Asp69Arg,Asp69Lys和Gly1Lys替代物取消了结合,可能是由于改变了柱状表面电荷和与受体膜的静电相互作用.
- 在酸乙醇胺 (PE) 缺乏的接受者中,挽救了结合,证实了PE相互作用的作用.
结论:
- 由于它们在DNA转移中的关键作用,Gly1和Asp69受到强大的选择性压力.
- 柱体表面的精确静电和静电性质对于高效的细菌结合至关重要.
- 这些发现提供了细菌交配柱功能和宿主-病原体相互作用的分子机制的见解.
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