A Sodium-Sensitive Salt Bridge in the Na+/H+ Antiporter NhaA
نویسندگان
چکیده
منابع مشابه
Periplasm-facing model of the NhaA antiporter
a Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, TelAviv University, Ramat Aviv 69978, Israel; b Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel; c Department of Chemical Engineering, Polymer Research Center, Life Sciences and Technologies Research Center, Boğa...
متن کاملMechanism of pH-dependent activation of the sodium-proton antiporter NhaA
Escherichia coli NhaA is a prototype sodium-proton antiporter, which has been extensively characterized by X-ray crystallography, biochemical and biophysical experiments. However, the identities of proton carriers and details of pH-regulated mechanism remain controversial. Here we report constant pH molecular dynamics data, which reveal that NhaA activation involves a net charge switch of a pH ...
متن کاملCrystal structure of the sodium–proton antiporter NhaA dimer and new mechanistic insights
Sodium-proton antiporters rapidly exchange protons and sodium ions across the membrane to regulate intracellular pH, cell volume, and sodium concentration. How ion binding and release is coupled to the conformational changes associated with transport is not clear. Here, we report a crystal form of the prototypical sodium-proton antiporter NhaA from Escherichia coli in which the protein is seen ...
متن کاملProton-sodium stoichiometry of NhaA, an electrogenic antiporter from Escherichia coli.
The H+:Na+ exchange stoichiometry of NhaA, a sodium-proton antiporter coded by the nhaA gene of Escherichia coli, has been determined using purified NhaA protein reconstituted into sodium-loaded proteoliposomes. One approach involved measuring, in parallel experiments, the Na+ efflux and H+ influx from such proteoliposomes and calculating the stoichiometry from the ratio of these fluxes. A seco...
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gradient for activation, both the wt and the pH-shifted G338S variant exhibit highly symmetrical transport activity with bell shaped pH dependencies, but the optimal pH was shifted 1.8 pH units to the acidic range in the variant. In both strains the pH dependence was associated with a systematic increase of the Km for Na + at acidic pH. Under symmetrical Na + concentration with a pH gradient fo...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 2013
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2012.11.1128