Characterization of pyruvate uptake in Escherichia coli K-12

• Published in: PloS one Vol. 8; no. 6; p. e67125
• Main Authors: Kreth, Jens, Lengeler, Joseph W, Jahreis, Knut
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 20.06.2013; Public Library of Science (PLoS)
• Subjects: Bacteria; Biological Transport - drug effects; Biological Transport - genetics; Biology; Carbohydrates; Carbon; Carbon sources; Dehydrogenases; E coli; Escherichia coli; Escherichia coli - genetics; Escherichia coli - growth & development; Escherichia coli - metabolism; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Excretion; Glycerol; Growth conditions; Kinetics; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Metabolism; Metabolites; Mutation; Plasmids; Potassium; Potassium - pharmacology; Proteins; Pyruvates - metabolism; Pyruvates - pharmacokinetics; Pyruvic acid; Pyruvic Acid - metabolism; Pyruvic Acid - pharmacokinetics; Substrates; Transport; Oklahoma; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0067125

The monocarboxylate pyruvate is an important metabolite and can serve as sole carbon source for Escherichia coli. Although specific pyruvate transporters have been identified in two bacterial species, pyruvate transport is not well understood in E. coli. In the present study, pyruvate transport was investigated under different growth conditions. The transport of pyruvate shows specific activities depending on the growth substrate used as sole carbon source, suggesting the existence of at least two systems for pyruvate uptake: i) one inducible system and probably highly specific for pyruvate and ii) one system active under non-induced conditions. Using the toxic pyruvate analog 3-fluoropyruvate, a mutant was isolated unable to grow on and transport pyruvate. Further investigation revealed that a revertant selected for growth on pyruvate regained the inducible pyruvate transport activity. Characterization of pyruvate excretion showed that the pyruvate transport negative mutant accumulated pyruvate in the growth medium suggesting an additional transport system for pyruvate excretion. The here presented data give valuable insight into the pyruvate metabolism and transport of E. coli suggesting the presence of at least two uptake systems and one excretion system to balance the intracellular level of pyruvate.