Role of hexose transport in control of glycolytic flux in Saccharomyces cerevisiae
Date
2004
Authors
Elbing K.
Larsson C.
Bill R.M.
Albers E.
Snoep J.L.
Boles E.
Hohmann S.
Gustafsson L.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The yeast Saccharomyces cerevisiae predominantly ferments glucose to ethanol at high external glucose concentrations, irrespective of the presence of oxygen. In contrast, at low external glucose concentrations and in the presence of oxygen, as in a glucose-limited chemostat, no ethanol is produced. The importance of the external glucose concentration suggests a central role for the affinity and maximal transport rates of yeast's glucose transporters in the control of ethanol production. Here we present a series of strains producing functional chimeras between the hexose transporters Hxt1 and Hxt7, each of which lias distinct glucose transport characteristics. The strains display a range of decreasing glycolytic rates resulting in a proportional decrease in ethanol production. Using these strains, we show for the first time that at high glucose levels, the glucose uptake capacity of wild-type S. cerevisiae does not control glycolytic flux during exponential batch growth. In contrast, our chimeric Hxt transporters control the rate of glycolysis to a high degree. Strains whose glucose uptake is mediated by these chimeric transporters will undoubtedly provide a powerful tool with which to examine in detail the mechanism underlying the switch between fermentation and respiration in S. cerevisiae and will provide new tools for the control of industrial fermentations.
Description
Keywords
Chemostats, Ethanol, Fermentation, Glucose, Oxygen, Glucose-limited chemostats, Glycolysis, Glycolytic rates, Industrial fermentations, Yeast, chimeric protein, glucose transporter, protein hxt1, protein hxt7, unclassified drug, microbiology, alcohol production, article, batch cell culture, binding affinity, concentration response, fermentation optimization, fermentation technique, glucose metabolism, glucose transport, glucose transport system, glycolysis, hexose transport, nonhuman, oxygen consumption, Saccharomyces cerevisiae, strain identification, transport kinetics, wild type, Biological Transport, Ethanol, Genotype, Glycolysis, Hexoses, Homeostasis, Kinetics, Saccharomyces cerevisiae, Saccharomyces, Saccharomyces cerevisiae
Citation
Applied and Environmental Microbiology
70
9
70
9