Species differences in bacterial NhaA Na/H exchangers |
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Authors: | Octavian Călinescu,Eva Danner,Marc Bö hm,Carola Hunte,Klaus Fendler |
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Affiliation: | 1. Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Frankfurt am Main, Germany;2. Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany;3. Institute for Biochemistry and Molecular Biology, ZBMZ, BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany |
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Abstract: | Bacteria have adapted their NhaA Na+/H+ exchangers responsible for salt homeostasis to their different habitats. We present an electrophysiological and kinetic analysis of NhaA from Helicobacter pylori and compare it to the previously investigated exchangers from Escherichia coli and Salmonella typhimurium. Properties of all three transporters are described by a simple model using a single binding site for H+ and Na+. We show that H.pylori NhaA only has a small acidic shift of its pH-dependent activity profile compared to the other transporters and discuss why a more drastic change in its pH activity profile is not physiologically required. |
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Keywords: | ACMA, 9-amino-6-chloro-2-methoxyacridine EcNhaA, NhaA Na+/H+ antiporter from E. coli HpNhaA, NhaA Na+/H+ antiporter from H. pylori IPTG, isopropyl-beta-d-thiogalactopyranoside SSM, solid-supported membrane StNhaA, NhaA Na+/H+ antiporter from S. typhimurium |
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