Project description:Up-regulation of motility genes and biosynthesis genes were found in the pck expressing high ATP cell by transcriptome analysis while catabolism genes were down-regulated. Keywords: response depends on intracellular ATP concentration derived by pck or ppc overexpression 1. pck or ppc overexpressing E. coli at early log phase using glucose-minimal medium 2. pck or ppc overexpressing E. coli at chemostat culture (D=0.1 h-1)using LB-glucose medium
Project description:Up-regulation of motility genes and biosynthesis genes were found in the pck expressing high ATP cell by transcriptome analysis while catabolism genes were down-regulated. Keywords: response depends on intracellular ATP concentration derived by pck or ppc overexpression
Project description:We have previously reported that phosphoenolpyruvate carboxykinase(Pck) overexpression under glycolytic conditions enables Escherichia coli to harbor a high intracellular ATP pool resulting in enhanced recombinant protein synthesis and biohydrogen production. To understand possible reasons of the high ATP haboring cell, we carried out transcriptome and metabolic flux analysis.
Project description:Enzyme IIANtr (encoded by ptsN gene) is a component of the nitrogen phosphotransferase system (PTS). It has previously been shown that the dephosphorylated form of EIIANtr is required for the derepression of ilvBN encoding acetohydroxy acid synthase I (AHAS I) catalyzing the first step common to biosynthesis of branched-chain amino acids. Here we examine the effect of deletion of ptsN gene on global gene expression by microarray analysis. Most of the genes down-regulated in a ptsN mutant are controlled by sigma 70, while all the up-regulated genes are controlled by sigma S. As intracellular levels of sigma factors in the ptsN mutant were similar to those of the wild-type strain, this implied that the balance of sigma activities is modified by ptsN deletion.
Project description:Metabolic cofactors such as NADH and ATP play important roles in a large number of cellular reactions and it is of great interest to dissect the role of these cofactors in different aspects of metabolism. Towards this goal, we overexpressed NADH oxidase and the soluble F1-ATPase in Escherichia coli to lower the level of NADH and ATP, respectively. We used a systems biology approach to study the response to these perturbations by measuring global transcription profiles, metabolic fluxes and the metabolite levels. We integrated information from the different measurements using network-based methods to identify high-scoring networks in a global interaction map that included protein interactions, transcriptional regulation and metabolism. The results revealed that the action of many global transcription factors such as ArcA, Fnr, CRP and IHF commonly involved both NADH and ATP while others were influential only in one of the pertubations. In general, overexpressing NADH oxidase invokes response in widespread aspects of metabolism involving the redox cofactors (NADH and NADPH) while ATPase has a more focused response to restore ATP level by enhancing proton translocation mechanisms and repressing biosynthesis. Interestingly, NADPH played a key role in restoring redox homeostasis through the concerted activity of isocitrate dehydrogenase and UdhA transhydrogenase. We present a reconciled network of regulation that illustrates the overlapping and distinct aspects of metabolism controlled by NADH and ATP. Our study contributes to the general understanding of redox and energy metabolism and should help in developing metabolic engineering strategies in E. coli.