K+ influx by Kup in Escherichia coli is accompanied by a decrease in H+ efflux.
Escherichia coli accumulates K+ by means of multiple uptake systems of which Kup is the major transport system at acidic pH. In cells grown under fermentative conditions at pH 5.5, K+ influx by a wild-type strain upon hyper-osmotic stress at pH 5.5 was accompanied by a marked decrease in H+ efflux, with a 1:1 ratio of K+ to H+ fluxes. This was observed with cells treated with N,N'-dicyclohexylcarbodiimide. Similar results with a mutant defective in Kdp and TrkA but with a functional Kup system but not in a mutant defective in Kdp and Kup but having an active TrkA system suggest that Kup operates as a H+ -K+ -symporter.
Zakharyan
E
E
Department of Biophysics of the Biological Faculty, Yerevan State University, 1 Alex Manougian Str., 375049 Yerevan, Armenia.
Trchounian
A
A
D000251:Adenosine Triphosphatases / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D017136:Ion Transport; D008565:Membrane Proteins / Q000378:metabolism*; D009997:Osmotic Pressure; D011188:Potassium / Q000378:metabolism*; D018892:Proton-Motive Force
D002352:Carrier Proteins; D008565:Membrane Proteins; D006859:Hydrogen; D000251:Adenosine Triphosphatases; D011188:Potassium