O-2 as the regulatory signal for FNR-dependent gene regulation in Escherichia coli
O-2 as the regulatory signal for FNR-dependent gene regulation in Escherichia coli
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DOI：
10.1128/jb.178.15.4515-4521.1996
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发表时间：
1996-08-01
影响因子：
3.2
通讯作者：
Unden, G
中科院分区：
文献类型：
--
作者：
Becker, S;Holighaus, G;Unden, G
用Oxystat研究了大肠杆菌中FNR依赖基因表达模式的变化，这是培养基中O-2张力（pO（2））的函数。然而，产生半最大抑制的pO（2）值（pO（0.5））取决于特定的启动子，并且在1和5毫巴之间变化（1巴= 10（5）Pa）。ArcA调节的琥珀酸脱氢酶基因的pO（0.5）值在相同的范围内（pO（0.5）= 4.6毫巴）。在这些pO（2）值下，可以计算出细胞质通过扩散被良好地供应了O-2。因此，细胞内O-2可以为FNR提供信号，这表明不需要信号传递链。有氧呼吸酶和辅酶的遗传失活对FNR调控基因的pO（0.5）没有影响或影响有限。因此，无论是有氧呼吸的成分，也不是他们的氧化还原状态的主要网站为O-2传感，支持细胞内O-2的意义。非氧化还原活性的结构O-2类似物如CO、CN-和N-3（-）不能模拟O-2在厌氧条件下对FNR调节基因的作用，也不能降低O-2在有氧条件下的抑制作用。
With an oxystat, changes in the pattern of expression of FNR-dependent genes from Escherichia coli were studied as a function of the O-2 tension (pO(2)) in the medium, Expression of all four tested genes was decreased by increasing O-2. However, the pO(2) values that gave rise to half-maximal repression (pO(0.5)) were dependent on the particular promoter and varied between 1 and 5 millibars (1 bar = 10(5) Pa). The pO(0.5), value for the ArcA-regulated succinate dehydrogenase genes was in the same range (pO(0.5) = 4.6 millibars), At these pO(2) values, the cytoplasm can be calculated to be well supplied with O-2 by diffusion. Therefore, intracellular O-2 could provide the signal to FNR, suggesting that there is no need for a signal transfer chain, Genetic inactivation of the enzymes and coenzymes of aerobic respiration had no or limited effects on the pO(0.5) of FNR-regulated genes. Thus, neither the components of aerobic respiration nor their redox state are the primary sites for O-2 sensing, supporting the significance of intracellular O-2. Non-redox-active, structural O-2 analogs like CO, CN-, and N-3(-) could not mimic the effect of O-2 on FNR-regulated genes under anaerobic conditions and did not decrease the inhibitory effect of O-2 under aerobic conditions.