title: Species differences in bacterial NhaA Na+/H+ exchangers.
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.
authors.affiliation: Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
authors.forename: Octavian
authors.initials: O
authors.lastname: Călinescu
authors.affiliation: Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Danner
authors.affiliation: Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Böhm
authors.affiliation: Institute for Biochemistry and Molecular Biology, ZBMZ, BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
authors.forename: Carola
authors.initials: C
authors.lastname: Hunte
authors.affiliation: Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Frankfurt am Main, Germany. Electronic address: klaus.fendler@biophys.mpg.de.
authors.forename: Klaus
authors.initials: K
authors.lastname: Fendler
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D055724:Electrophysiological Phenomena; D016480:Helicobacter pylori; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D017923:Sodium-Hydrogen Exchangers
keywords: Cation/proton antiport; Escherichia coli; Helicobacter pylori; NhaA; Salmonella typhimurium; Solid supported membrane