Analysis of Escherichia coli mutants with a linear respiratory chain.
Analysis of Escherichia coli mutants with a linear respiratory chain.
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DOI：
10.1371/journal.pone.0087307
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Bettenbrock K
中科院分区：
文献类型：
--
作者：
Steinsiek S;Stagge S;Bettenbrock K
大肠杆菌的呼吸链有分支，使细胞能够灵活地应对不断变化的环境条件。它由NADH：泛醌氧化还原酶NADH脱氢酶I和II以及三种末端氧化酶组成。它们在能量效率（质子易位）和它们对不同的醌/醌类和氧的亲和力方面有所不同。为了分析支链电子传递链相对于线性传递链的优势，并评估不同末端氧化酶的使用如何决定不同氧浓度下的生长行为，我们创建了一组等基因突变菌株，它们缺乏NADH脱氢酶I以及两种末端氧化酶，从而产生了具有线性呼吸链的菌株。在限定供氧、调节好氧、厌氧和不同微氧条件下，对这些菌株进行葡萄糖限化实验分析。与野生型菌株MG1655相比，突变菌株即使在有氧条件下也能产生乙酸。菌株TBE032缺乏NADH脱氢酶I，表达细胞色素bd-II作为唯一的末端氧化酶，在好氧条件下乙酸生成率最高。这支持了细胞色素bd-II末端氧化酶在高氧条件下不能催化喹啉池的有效氧化，而主要在限氧条件下起作用的观点。研究了双组分体系ArcBA的调控因子ArcA和Fnr对不同氧浓度响应的主要转录因子的磷酸化。其磷酸化模式在突变株中发生了改变。与野生型菌株相比，ArcA的去磷酸化和失活始于较低的好氧水平。值得注意的是，突变不仅影响了微代谢和有氧代谢，而且影响了呼吸链不重要的无氧代谢。
The respiratory chain of E. coli is branched to allow the cells' flexibility to deal with changing environmental conditions. It consists of the NADH:ubiquinone oxidoreductases NADH dehydrogenase I and II, as well as of three terminal oxidases. They differ with respect to energetic efficiency (proton translocation) and their affinity to the different quinone/quinol species and oxygen. In order to analyze the advantages of the branched electron transport chain over a linear one and to assess how usage of the different terminal oxidases determines growth behavior at varying oxygen concentrations, a set of isogenic mutant strains was created, which lack NADH dehydrogenase I as well as two of the terminal oxidases, resulting in strains with a linear respiratory chain. These strains were analyzed in glucose-limited chemostat experiments with defined oxygen supply, adjusting aerobic, anaerobic and different microaerobic conditions. In contrast to the wild-type strain MG1655, the mutant strains produced acetate even under aerobic conditions. Strain TBE032, lacking NADH dehydrogenase I and expressing cytochrome bd-II as sole terminal oxidase, showed the highest acetate formation rate under aerobic conditions. This supports the idea that cytochrome bd-II terminal oxidase is not able to catalyze the efficient oxidation of the quinol pool at higher oxygen conditions, but is functioning mainly under limiting oxygen conditions. Phosphorylation of ArcA, the regulator of the two-component system ArcBA, besides Fnr the main transcription factor for the response towards different oxygen concentrations, was studied. Its phosphorylation pattern was changed in the mutant strains. Dephosphorylation and therefore inactivation of ArcA started at lower aerobiosis levels than in the wild-type strain. Notably, not only the micro- and aerobic metabolism was affected by the mutations, but also the anaerobic metabolism, where the respiratory chain should not be important.
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影响因子：
4.3
作者：
Borisov, Vitaliy B.;Gennis, Robert B.;Hemp, James;Verkhovsky, Michael I.
通讯作者：
Verkhovsky, Michael I.
DOI：
10.1007/bf00267454
发表时间：
1991-10-01
期刊：
MOLECULAR & GENERAL GENETICS
影响因子：
--
作者：
DASSA, J;FSIHI, H;BOQUET, PL
通讯作者：
BOQUET, PL
影响因子：
3.6
作者：
BONGAERTS, J;ZOSKE, S;UNDEN, G
通讯作者：
UNDEN, G
影响因子：
3.2
作者：
Bekker, Martijn;Alexeeva, Svetlana;Hellingwerf, Klaas
通讯作者：
Hellingwerf, Klaas
影响因子：
2.8
作者：
Green, Jason;Carter, Emma;Murphy, Damien M.
通讯作者：
Murphy, Damien M.