地质细菌的结构显示出分泌而不是纳米线的行为
Yangqi Gu1,2, Vishok Srikanth1,3, Aldo I Salazar-Morales1,3
1Microbial Sciences Institute Yale University, West Haven, CT, USA.
Nature
|September 2, 2021
概括
地质细菌种类使用,而不是纳米线,用于电子传输. 这些由PilA-N和PilA-C蛋白质组成的 pili是周等离子体,对纳米线分泌至关重要,影响生物能源和生物修复应用.
科学领域:
- 微生物学和微生物生态学
- 生物能源和生物修复
- 结构生物学和纳米技术
背景情况:
- 地质细菌物种通过微生物纳米线促进细胞外电子转移,这对环境过程和生物技术应用至关重要.
- 此前,这些纳米线被认为仅由PilA-N蛋白组成的4型.
- 之前的结构研究表明,在电子转移过程中,细胞产生细胞染色体OmcS和OmcZ的纳米线,而不是 pili.
研究的目的:
- 研究PilA-N和PilA-C蛋白质在Geobacter sulfurreducens中的结构和功能作用.
- 阐明Geobacter物种中纳米线组装和分泌的机制.
- 确定 PilA-N-C pili 对细胞外电子转移和相关应用的贡献.
主要方法:
- 使用冷电子显微镜来确定PilA-N-C纤维的结构.
- 生物化学分析评估了PilA-N和PilA-C蛋白的共聚变.
- 用基因操作 (pilA-N删除和复制) 来研究这些蛋白质在纳米线分泌中的作用.
主要成果:
- 在细胞外电子转移过程中,Geobacter sulfurreducens组装了异体皮质 (PilA-N-C).
- 与OmcZ纳米导线相比,PilA-N-C导线的导电性显著降低,其功能与2型分泌伪导线类似.
- OmcS和OmcZ纳米线的分泌取决于PilA-N-C纤维的存在和正确组装.
结论:
- 这项研究驳斥了长期以来在Geobacter中介于细胞外电子转移的4型 pili模型.
- PilA-N-C pili作为功能OmcS和OmcZ纳米线的分泌所必需的转位机制.
- 了解这种机制对电子转移微生物的进化和合成蛋白质纳米线的设计有广泛的影响.
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