Mode of action of colicin Ia: effect of colicin on the Escherichia coli proton electrochemical gradient.

Publisher Website
Google Scholar
Abstract
By use of the technique of flow dialysis, the membrane potential (.DELTA..psi.) and pH gradient (.DELTA.pH) were measured in colicin Ia-treated E. coli K-12 cells and in membrane vesicles prepared from such cells. Although such cells and vesicles generate a transmembrane .DELTA.pH at pH 5.5, they do not generate a transmembrane .DELTA..psi.. G-6-P uptake by cells is stimulated at pH 5.5 and inhibited at pH 7.5 by colicin Ia treatment. Proline uptake is demonstrated to be inhibited progressively at pH 5.5, 6.6 and 7.5 in colicin Ia-treated cells. These data provide strong evidence for a colicin Ia-induced membrane depolarization and indicate that the membrane becomes permeable to ion(s) other than protons after treatment with colicin Ia.