缺乏对细胞染色体纤维作为细胞外电子转移管道的生理证据
Ingrid A Schwarz1, Baha Alsaqri1, Yassir Lekbach2
1Department of Biomolecular Sciences, Central Connecticut State University, New Britain, Connecticut, USA.
mBio
|May 8, 2024
概括
在长距离的细胞外电子转移和Fe (III) 氧化物减少中,Geobacter sulfurreducens使用导电性 pili (e-pili),而不是细胞染色体纤维. 这一发现重新定义了微生物电子运输机制.
科学领域:
- 微生物学 微生物学
- 生物化学 生物化学
- 环境科学 环境科学
背景情况:
- 细胞外电子转移 (EET) 对微生物新陈代谢和生物地球化学循环至关重要.
- 以前人们认为细胞染色体纤维是像Geobacter sulfurreducens.这样的细菌中远程EET的主要导管.
- 支持细胞染色体纤维在Fe (III) 氧化物减少中的作用的证据是基于对OmcS缺乏菌株的研究.
研究的目的:
- 重新评估细胞染色体纤维对比Pili在Geobacter sulfurreducens细胞外电子转移中的作用.
- 调查特定细胞外结构对Fe (III) 氧化物减少的功能性贡献.
- 为了确定能够在G. sulfurreducens.中实现远程电子传输的关键导电结构.
主要方法:
- 在G. sulfurreducens.中,对编码纤维形成细胞染色体 (OmcS和其他) 的基因进行遗传删除.
- 一个三重细胞染色体突变的构建和分析.
- 在大肠杆菌中,G. sulfurreducens PilA pilin的异质表达形成了直径为3nm的 pili.
- 修改pilin基因以改变导电性.
主要成果:
- 缺乏OmcS和三重细胞染色体突变体显示野生类型的Fe (III) 氧化物减少水平.
- 删除细胞染色体基因并没有改变细胞外纤维的形态或导电性.
- 由异质表达的 PilA 形成的导电性 pili (e-pili) 是减少 Fe (III) 氧化物所必不可少的.
- 抑制Fe(III) 氧化物还原发生在pilin基因被修改以产生导电性较差的 pili.
结论:
- 导电性皮利 (e-pili),而不是细胞染色体纤维,是Geobacter sulfurreducens中长距离细胞外电子转移的主要导管.
- 的导电性和3纳米直径对于高效的Fe (III) 氧化物减少至关重要.
- 关于细胞染色体纤维在EET中的作用的先前假设需要根据新的生理学证据进行修订.
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