一种基于黄素的细胞外电子转移机制在各种格拉姆阳性细菌
Samuel H Light1, Lin Su2,3, Rafael Rivera-Lugo1
1Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
Nature
|September 14, 2018
概括
利斯特里亚单细胞菌利用一种基于黄素的新型细胞外电子转移 (EET) 系统进行生长和生存. 这种机制与已知的途径不同,涉及特定的基因和黄素,影响微生物群落.
科学领域:
- 微生物学和微生物生理学
- 生物电化学系统
- 遗传学和分子生物学
背景情况:
- 细胞外电子转移 (EET) 对于微生物生物电化学过程至关重要,但除了基于海姆的系统之外的机制尚不清楚.
- 矿物呼吸细菌通常采用复杂的基于海姆的电子转移途径.
- 其他ETT途径的存在和机制基础在很大程度上尚未被探索.
研究的目的:
- 阐明食物传播病原体Listeria monocytogenes细胞外电子转移的机制.
- 确定基于黄素的新型EET系统的遗传基础和关键组成部分.
- 研究这种EET机制在微生物群落中的生理作用和流行程度.
主要方法:
- 进行基因查,以识别L. monocytogenes突变体,其细胞外铁还原酶活性降低.
- 对ETE负责的八个基因位点的识别和特征.
- 生物化学测定和基因分析以确定特定基因和分子的作用 (NADH脱酶,子池,黄蛋白,黄素穿).
主要成果:
- 在L. monocytogenes中发现了一种编码专门的NADH脱酶并促进基于黄素的EET的新型八基因位点.
- 这种系统将电子运送到不同的池中,并利用细胞外的黄蛋白和黄素穿器将电子传送到铁或电极等受体.
- EET激活支持非发酵碳来源的生长,EET突变在小鼠肠道中表现出竞争性缺陷;在Firmicutes中,ortologs广泛存在.
结论:
- L. monocytogenes采用一种独特的黄素依赖EET机制,与基于血的系统不同,使电子转移到外部受体.
- 这种基于黄素的EET系统对于利用某些碳来源至关重要,并在与宿主相关的环境中提供竞争优势.
- 已识别的EET基因和机制在Firmicutes族中普遍存在,这表明它对电致细菌具有广泛的生态和病原性相关性.
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