Topological Analysis of NhaA, a Na+/H+ Antiporter from Escherichia coli
نویسندگان
چکیده
منابع مشابه
Topological analysis of NhaA, a Na+/H+ antiporter from Escherichia coli.
Analysis of the hydropathic profile of the amino acid sequence of NhaA, a Na+/H+ antiporter from Escherichia coli has previously suggested the existence of 11 putative transmembrane segments (Taglicht, D., Padan, E., and Schuldiner, S. (1991) J. Biol. Chem. 266, 11289-11294). In the present work to test the location of the C terminus, right-side-out and inside-out membrane vesicles were digeste...
متن کاملANTIPORTER NhaA FROM ESCHERICHIA COLI. AN ELECTROPHYSIOLOGICAL STUDY*
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...
متن کاملTransport Mechanism and pH Regulation of the Na+/H+ Antiporter NhaA from Escherichia coli
Using an electrophysiological assay the activity of NhaA was tested in a wide pH range from pH 5.0 to 9.5. Forward and reverse transport directions were investigated at zero membrane potential using preparations with inside-out and right side-out-oriented transporters with Na(+) or H(+) gradients as the driving force. Under symmetrical pH conditions with a Na(+) gradient for activation, both th...
متن کاملMulticonformation continuum electrostatics analysis of the NhaA Na+/H+ antiporter of Escherichia coli with functional implications.
Sodium proton antiporters are essential enzymes that catalyze the exchange of sodium ions for protons across biological membranes. Protonations and deprotonations of individual amino acid residues and of clusters formed by these residues play an important role in activating these enzymes and in the mechanism of transport. We have used multiconformation continuum electrostatics method to investi...
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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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1996
ISSN: 0021-9258
DOI: 10.1074/jbc.271.50.32288