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Effect of the global redox sensing/regulation networks on Escherichia coli and metabolic flux distribution based on C-13 labeling experiments

Paper ID Volume ID Publish Year Pages File Format Full-Text
31821 44841 2006 9 PDF Available
Title
Effect of the global redox sensing/regulation networks on Escherichia coli and metabolic flux distribution based on C-13 labeling experiments
Abstract

Escherichia coli has several elaborate sensing mechanisms for response to the availability of oxygen and the presence of other electron acceptors. Among them, the one component Fnr protein and the two-component Arc system coordinate the adaptive responses to oxygen availability. To systematically investigate the contribution of Arc- and Fnr-dependent regulation in catabolism, glucose-limited chemostat cultures were conducted on wild-type E. coli, an arcA mutant, an fnr mutant, and an arcAfnr double mutant strains under a well-defined semi-aerobic condition. The metabolic flux distributions of the cultures of these strains were estimated based on C-13 labeling experiments. It was shown that the oxidative pentose phosphate (PP) pathway was functioning at low level under semi-aerobic condition. The fluxes through pyruvate dehydrogenase (PDH) and tricarboxylic acid (TCA) cycle were found to be lower in the arcA mutant and the arcAfnr double mutant strains than that in the wild-type strain, although the expression of the genes involved in these pathways have been proved to be derepressed in the mutant strains ([Shalel-Levanon, S., San, K.Y., Bennett, G.N., 2005a. Effect of ArcA and FNR on the expression of genes related to the oxygen regulation and the glycolysis pathway in Escherichia coli under microaerobic growth conditions. Biotechnol. Bioeng. 92, 147–159; Shalel-Levanon, S., San, K.Y., Bennett, G.N., 2005c. Effect of oxygen, and ArcA and FNR regulators on the expression of genes related to the electron transfer chain and the TCA cycle in Escherichia coli. Metab. Eng. 7, 364–374]). The significantly higher lactate production in the arcAfnr double mutant strain was shown to be an indirect effect caused by the reduced pyruvate formate-lyase (PFL) and PDH fluxes as well as the intracellular redox state.

Keywords
E. coli; ArcA; Fnr; C-13 labeling; Metabolic flux distribution; Redox sensing/regulation networksPEP, phosphoenolpyruvate; PYR, pyruvate; G6P, glucose 6-phosphate; F6P, fructose 6-phosphate; GAP, glyceraldehyde 3-phosphate; 3PG, 3-phosphoglycerate; AcCoA,
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Effect of the global redox sensing/regulation networks on Escherichia coli and metabolic flux distribution based on C-13 labeling experiments
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Publisher
Database: Elsevier - ScienceDirect
Journal: Metabolic Engineering - Volume 8, Issue 6, November 2006, Pages 619–627
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
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Any Questions? feel free to contact us