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Glucose becomes one of the worst carbon sources for E.coli on poor nitrogen sources due to suboptimal levels of cAMP

Author(s): Bren, Anat; Park, Junyoung O.; Towbin, Benjamin D.; Dekel, Erez; Rabinowitz, Joshua D.; et al

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Abstract: In most conditions, glucose is the best carbon source for E. coli: it provides faster growth than other sugars, and is consumed first in sugar mixtures. Here we identify conditions in which E. coli strains grow slower on glucose than on other sugars, namely when a single amino acid (arginine, glutamate, or proline) is the sole nitrogen source. In sugar mixtures with these nitrogen sources, E. coli still consumes glucose first, but grows faster rather than slower after exhausting glucose, generating a reversed diauxic shift. We trace this counterintuitive behavior to a metabolic imbalance: levels of TCA-cycle metabolites including α-ketoglutarate are high, and levels of the key regulatory molecule cAMP are low. Growth rates were increased by experimentally increasing cAMP levels, either by adding external cAMP, by genetically perturbing the cAMP circuit or by inhibition of glucose uptake. Thus, the cAMP control circuitry seems to have a ‘bug’ that leads to slow growth under what may be an environmentally rare condition.
Publication Date: Jul-2016
Electronic Publication Date: 25-Apr-2016
Citation: Bren, Anat, Park, Junyoung O, Towbin, Benjamin D, Dekel, Erez, Rabinowitz, Joshua D, Alon, Uri. (2016). Glucose becomes one of the worst carbon sources for E.coli on poor nitrogen sources due to suboptimal levels of cAMP. Scientific Reports, 6 (1), 10.1038/srep24834
DOI: doi:10.1038/srep24834
EISSN: 2045-2322
Pages: 6:24834-1 - 6:24834-15
Type of Material: Journal Article
Journal/Proceeding Title: Scientific Reports
Version: Final published version. This is an open access article.



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