Growth phase-dependent regulation of nuoA-N expression in Escherichia coli K-12 by the Fis protein: upstream binding sites and bioenergetic significance
Growth phase-dependent regulation of nuoA-N expression in Escherichia coli K-12 by the Fis protein: upstream binding sites and bioenergetic significance
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DOI：
10.1007/s004380051153
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发表时间：
1999-12
期刊：
影响因子：
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通讯作者：
B. Wackwitz;J. Bongaerts;S. Goodman;G. Unden
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文献类型：
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作者：
B. Wackwitz;J. Bongaerts;S. Goodman;G. Unden
大肠杆菌K-12的nuoA-Noperon编码质子泵NADH脱氢酶I，其表达受生长期依赖性调控。在呼吸生长条件下，表达在早期指数中被刺激，并且在较低程度上在晚期指数和静止生长期被刺激。在早期指数生长期的刺激没有观察到infismutants，这是缺乏的生长期响应调节Fis。替代σ因子RpoS和整合宿主因子（IHF）均不参与该操纵子的生长期依赖性调节。当与nuopromotor DNA孵育时，分离的Fis蛋白在凝胶迁移实验中形成三种阻滞复合物。DNA酶I足迹法确定了三个不同的Fis结合位点，分别位于nuoA-N，T1主要转录本起始端上游237 bp（fis 1），197 bp（fis 2）和139 bp（fis 3）。fis 1、fis 2和fis 3的半数最大结合所需的蛋白浓度分别为约20 nM、40 nM和100 nM Fis。IHF蛋白结合转录本T2起始上游82 bp，结合的半最大浓度为50 nM。由于Fis的生长阶段依赖性调节，偶联NADH脱氢酶I的合成在早期指数生长期间相对于非偶联NADH脱氢酶II的合成增加。这确保了在需要大量ATP的条件下更高的ATP产量。
The expression of thenuoA-Noperon ofEscherichia coliK-12, which encodes the proton-pumping NADH dehydrogenase I is modulated by growth phase-dependent regulation. Under respiratory growth conditions, expression was stimulated in early exponential, and to a lesser extent in late exponential and stationary growth phases. The stimulation in the early exponential growth phase was not observed infismutants, which are deficient for the growth phase-responsive regulator Fis. Neither the alternative σ factor RpoS nor the integration host factor (IHF) are involved in growth phase-dependent regulation of this operon. When incubated withnuopromoter DNA, isolated Fis protein formed three retarded complexes in gel mobility experiments. DNase I footprinting identified three distinct binding sites for Fis, 237 bp (fis1), 197 bp (fis2) and 139 bp (fis3) upstream of the start of the major transcript ofnuoA-N, T1. The protein concentrations required for half-maximal binding tofis1,fis2andfis3were about 20 nM, 40 nM and 100 nM Fis, respectively. The IHF protein bound 82 bp upstream of the start of transcript T2 with a half-maximal concentration for binding of 50 nM. Due to the growth phase-dependent regulation by Fis, the synthesis of the coupling NADH dehydrogenase I is increased relative to that of the non-coupling NADH dehydrogenase II during early exponential growth. This ensures higher ATP yields under conditions where large amounts of ATP are required.