The metabolic potential of Escherichia coli BL21 in defined and rich medium
Creators: name: Li, Zhaopeng
name: Nimtz, Manfred
name: Rinas, Ursula
Publisher: name: London : BioMed Central Ltd.
Year: 2014
Subjects: subject: Escherichia coli
subject: pyruvate dehydrogenase
subject: Growth rate control
subject: Metabolic balance
subject: Overflow metabolism
subject: Proteome
subject: Stationary phase response
subject: Transcriptional control
subject: Two-dimensional gel electrophoresis
subject: Pentose Phosphate Pathway
subject: Ketone Oxidoreductases
subject: Glycolysis
subject: Escherichia coli Proteins
subject: Energy Metabolism
subject: Electrophoresis, Gel, Two-Dimensional
subject: Culture Media
subject: Citric Acid Cycle
subject: Carbon
subject: Amino Acids
subject: two dimensional gel electrophoresis
subject: transcription regulation
subject: respiratory chain
subject: protein synthesis
subject: protein folding
subject: pyruvate dehydrogenase complex
subject: amino acid synthesis
subject: bacterial growth
subject: bacterial metabolism
subject: bacterial phenomena and functions
subject: carbon metabolism
subject: cell protection
subject: citric acid cycle
subject: culture medium
subject: Escherichia coli BL21
subject: glycolysis
subject: metabolic balance
subject: metabolism
subject: nonhuman
subject: nutrient availability
subject: pentose phosphate cycle
subject: protein analysis
subject: protein degradation
subject: Dewey Decimal Classification::500 | Naturwissenschaften
subject: Dewey Decimal Classification::500 | Naturwissenschaften::570 | Biowissenschaften, Biologie

description: Background: The proteome reflects the available cellular machinery to deal with nutrients and environmental challenges. The most common E. coli strain BL21 growing in different, commonly employed media was evaluated using a detailed quantitative proteome analysis.Results: The presence of preformed biomass precursor molecules in rich media such as Luria Bertani supported rapid growth concomitant to acetate formation and apparently unbalanced abundances of central metabolic pathway enzymes, e.g. high levels of lower glycolytic pathway enzymes as well as pyruvate dehydrogenase, and low levels of TCA cycle and high levels of the acetate forming enzymes Pta and AckA. The proteome of cells growing exponentially in glucose-supplemented mineral salt medium was dominated by enzymes of amino acid synthesis pathways, contained more balanced abundances of central metabolic pathway enzymes, and a lower portion of ribosomal and other translational proteins. Entry into stationary phase led to a reconstruction of the bacterial proteome by increasing e.g. the portion of proteins required for scavenging rare nutrients and general cell protection. This proteomic reconstruction during entry into stationary phase was more noticeable in cells growing in rich medium as they have a greater reservoir of recyclable proteins from the translational machinery.Conclusions: The proteomic comparison of cells growing exponentially in different media reflected the antagonistic and competitive regulation of central metabolic pathways through the global transcriptional regulators Cra, Crp, and ArcA. For example, the proteome of cells growing exponentially in rich medium was consistent with a dominating role of phosphorylated ArcA most likely a result from limitations in reoxidizing reduced quinones in the respiratory chain under these growth conditions. The proteomic alterations of exponentially growing cells into stationary phase cells were consistent with stringent-like and stationary phase responses and a dominating control through DksA-ppGpp and RpoS.