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Transport of Na+ and K+ by an antiporter-related subunit from the Escherichia coli NADH dehydrogenase I produced in Saccharomyces cerevisiae

Gemperli, Anja ; Schaffitzel, Christiane ; Jakob, Claude ; Steuber, Julia

In: Archives of Microbiology, 2007, vol. 188, no. 5, p. 509-521

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    Titre
    • Transport of Na+ and K+ by an antiporter-related subunit from the Escherichia coli NADH dehydrogenase I produced in Saccharomyces cerevisiae
    Auteur
    • Gemperli, Anja. Department of Biochemistry, University of Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
    • Schaffitzel, Christiane. Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Schafmattstasse 20, 8093, Zürich, Switzerland
    • Jakob, Claude. Institute of Microbiology, Eidgenössische Technische Hochschule (ETH), Wolfgang-Pauli-Strasse 10, 8093, Zürich, Switzerland
    • Steuber, Julia. Department of Biochemistry, University of Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
    Type de document
    • Postprint
    Identifiant OAI-PMH
    • oai:doc.rero.ch:314513
    Summary
    The NADH dehydrogenase I from Escherichia coli is a bacterial homolog of the mitochondrial complex I which translocates Na+ rather than H+. To elucidate the mechanism of Na+ transport, the C-terminally truncated NuoL subunit (NuoLN) which is related to Na+/H+ antiporters was expressed as a protein A fusion protein (ProtA-NuoLN) in the yeast Saccharomyces cerevisiae which lacks an endogenous complex I. The fusion protein inserted into membranes from the endoplasmatic reticulum (ER), as confirmed by differential centrifugation and Western analysis. Membrane vesicles containing ProtA-NuoLN catalyzed the uptake of Na+ and K+ at rates which were significantly higher than uptake by the control vesicles under identical conditions, demonstrating that ProtA-NuoLN translocated Na+ and K+ independently from other complex I subunits. Na+ transport by ProtA-NuoLN was inhibited by EIPA (5-(N-ethyl-N-isopropyl)-amiloride) which specifically reacts with Na+/H+ antiporters. The cation selectivity and function of the NuoL subunit as a transporter module of the NADH dehydrogenase complex is discussed