An O2-sensing stressosome from a Gram-negative bacterium.
An O2-sensing stressosome from a Gram-negative bacterium.
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DOI：
10.1038/ncomms12381
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发表时间：
2016-08-04
影响因子：
16.6
通讯作者：
Weinert EE
中科院分区：
文献类型：
--
作者：
Jia X;Wang JB;Rivera S;Duong D;Weinert EE
细菌已经进化出多种途径来感知和响应不断变化的环境条件，包括在革兰氏阳性细菌中调节一般应激反应基因转录的应激体复合体。然而，革兰氏阳性应激体识别的信号分子尚未确定，这阻碍了我们对复合体内信号转导机制的理解。此外，在革兰氏阴性细菌中还没有描述类似的途径。在这里，我们描述了来自革兰氏阴性菌巴西弧菌的一个假定的应激体。传感器蛋白RsbR与Hem结合，并表现出对应激体复合体活性的配体依赖的控制。氧与血红素结合降低活性，而亚铁RsbR导致活性增加，这表明当细菌进入厌氧生长条件时，巴西弧菌应激体可能被激活。这些发现为研究应激体复合体中的配体依赖信号提供了一个模型系统，以及对弧菌物种中受氧依赖信号控制的潜在途径的洞察。应激体是一种多蛋白复合体，调节革兰氏阳性细菌中应激反应基因的表达。在这里，作者描述了一个来自革兰氏阴性细菌的应激体的特征，表明其中一个蛋白质成分通过结合的血红素感知氧气。
Bacteria have evolved numerous pathways to sense and respond to changing environmental conditions, including, within Gram-positive bacteria, the stressosome complex that regulates transcription of general stress response genes. However, the signalling molecules recognized by Gram-positive stressosomes have yet to be identified, hindering our understanding of the signal transduction mechanism within the complex. Furthermore, an analogous pathway has yet to be described in Gram-negative bacteria. Here we characterize a putative stressosome from the Gram-negative bacterium Vibrio brasiliensis. The sensor protein RsbR binds haem and exhibits ligand-dependent control of the stressosome complex activity. Oxygen binding to the haem decreases activity, while ferrous RsbR results in increased activity, suggesting that the V. brasiliensis stressosome may be activated when the bacterium enters anaerobic growth conditions. The findings provide a model system for investigating ligand-dependent signalling within stressosome complexes, as well as insights into potential pathways controlled by oxygen-dependent signalling within Vibrio species. The stressosome is a multiprotein complex that regulates the expression of stress response genes in Gram-positive bacteria. Here the authors characterize a stressosome from a Gram-negative bacterium, showing that one of the protein components senses oxygen through a bound haem.