Changes in substrate availability in Escherichia coli lead to rapid metabolite, flux and growth rate responses.
The interactions between the intracellular metabolome, fluxome and growth rate of Escherichia coli after sudden glycolytic/gluconeogenic substrate shifts are studied based on pulses of different substrates to an aerobic glucose-limited steady-state (dilution rate=0.1h(-1)). After each added glycolytic (glucose) and gluconeogenic (pyruvate and succinate) substrate pulse, no by-products were secreted and a pseudo steady state in flux and metabolites was achieved in about 30-40s. In the pulse experiments a large oxygen uptake capacity of the cells was observed. The in vivo dynamic responses showed massive reorganization and flexibility (1/100-14-fold change) of extra/intracellular metabolic fluxes, matching with large changes in the concentrations of intracellular metabolites, including reversal of reaction rate for pseudo/near equilibrium reactions. The coupling of metabolome and fluxome could be described by Q-linear kinetics. Remarkably, the three different substrate pulses resulted in a very similar increase in growth rate (0.13-0.3h(-1)). Data analysis showed that there must exist as yet unknown mechanisms which couple the protein synthesis rate to changes in central metabolites.
Department of Biotechnology, Delft University of Technology, Kluyver Centre for Genomics of Industrial Fermentation, Julianalaan 67, 2628 BC Delft, The Netherlands. hilal.taymaz@gmail.com
Hilal
H
Taymaz-Nikerel
Marjan
M
De Mey
Gino
G
Baart
Jo
J
Maertens
Joseph J
JJ
Heijnen
Walter
W
van Gulik
D000332:Aerobiosis / Q000187:drug effects; D048168:Escherichia coli K12 / Q000254:growth & development / Q000378:metabolism*; D005943:Gluconeogenesis / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology*; D006019:Glycolysis / Q000187:drug effects; D055442:Metabolome / Q000187:drug effects*; D019289:Pyruvic Acid / Q000494:pharmacology*; D019802:Succinic Acid / Q000494:pharmacology*; D013549:Sweetening Agents / Q000494:pharmacology*
D013549:Sweetening Agents; D019289:Pyruvic Acid; D019802:Succinic Acid; D005947:Glucose