Excess capacity of H+ ATPase and inverse respiratory control in Escherichia coli

Peter Ruhdal Jensen, Hans V. Westerhoff, Ole Michelsen

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    With succinate as free-energy source, Escherichia coli generating virtually all ATP by oxidative phosphorylation might be expected heavily to tax its ATP generating capacity. To examine this the H+-ATPase (ATP synthase) was modulated over a 30-fold range. Decreasing the amount of H+-ATPase reduced the growth rate much less than proportionally; the H+-ATPase controlled growth rate by lt 10%. This lack of control reflected excess capacity: the rate of ATP synthesis per H+-ATPase (the turnover number) increased by 60% when the number of enzymes was decreased by 40%. At 15% H+-ATPase, the enzyme became limiting and its turnover was increased even further, due to an increased driving force caused by a reduction in the total flux through the enzymes. At smaller reductions of (H+-ATPase) the total flux was not reduced, revealing a second cause for increased turnover number through increased membrane potential: respiration was increased showing that in E. coli, respiration and ATP synthesis are, in part, inversely coupled. Indeed, growth yield per O-2 decreased, suggesting significant leakage or slip at the high respiration rates and membrane potential found at low H+-ATPase concentrations, and explaining that growth yield may be increased by activating the H+-ATPase.
    Original languageEnglish
    JournalE M B O Journal
    Volume12
    Issue number4
    Pages (from-to)1277-1282
    Number of pages6
    ISSN0261-4189
    Publication statusPublished - 1993

    Keywords

    • Adenine Nucleotides
    • Bacterial Proteins
    • Energy Metabolism
    • Escherichia coli
    • Oxygen Consumption
    • Proton-Translocating ATPases
    • EC 3.6.3.14 Proton-Translocating ATPases
    • OXIDATIVE PHOSPHORYLATION
    • RESPIRATION
    • Facultatively Anaerobic Gram-Negative Rods Eubacteria Bacteria Microorganisms (Bacteria, Eubacteria, Microorganisms) - Enterobacteriaceae [06702] Escherichia coli
    • ATPASE 9000-83-3
    • 10064, Biochemistry studies - Proteins, peptides and amino acids
    • 10510, Biophysics - Bioenergetics: electron transport and oxidative phosphorylation
    • 10808, Enzymes - Physiological studies
    • 13003, Metabolism - Energy and respiratory metabolism
    • 31000, Physiology and biochemistry of bacteria
    • Biochemistry and Molecular Biophysics
    • Bioenergetics
    • Enzymology
    • Metabolism
    • Physiology

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