Changes in the cellular energy state affect the activity of the bacterial phosphotransferase system

J.M. Rohwer, Peter Ruhdal Jensen, Y. Shinohara, P.W. Postma, H.V. Westerhoff

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    The effect of different cellular free-energy states on the uptake of methyl alfa-D-glucopyranoside, an analoque of glucose, by Escherichia coli phosphoenolpyruvate:carbohydrate phosphotransferase system was investigated. The intracellular ATP/ADP ratio was varied by changing the expression of the atp operon, which codes for the H+-ATPase, or by adding an uncoupler of oxidative phosphorylation or an inhibitor of respiration. Corresponding initial phosphotransferase uptake rates were determined using an improved uptake assay that works with growing cells in steady state. The results show that the initial uptake rate was decreased under conditions of lowered intracellular ATP/ADP ratios, irrespective of which method was used to change the cellular energy state.. When either the expression of the atp operon was changed or 2,4-dinitrophenol was added to wild-type cells, the relationship between initial phosphotransferase uptake rate and the logaritm of the ATP/ADP ratio was approxomately linear. These results suggest that the cellular free-energy state, as reflected in the intracellular ATP/ADP ratio, plays an important role in regulating the activity of the phosphotransferase ssystem.
    Original languageEnglish
    JournalEuropean Journal of Biochemistry
    Volume235
    Pages (from-to)225-230
    ISSN0014-2956
    Publication statusPublished - 1996

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