Figure 5: pH dependence of MdfA-mediated Mdr.
From: Export of a single drug molecule in two transport cycles by a multidrug efflux pump
(a) pH-dependent drug resistance assay. The experiment was done as in Fig. 1b, with a pH-buffering agent (Bis-Tris-Propane) added to the medium to generate the pH indicated to the right. (b) Accumulation of Dq in ΔpH-dissipated cells. Dissipation of ΔpH was achieved by conducting the assay at pH 8 in the presence of 2 μM nigericin. The membranes were permeabilized to nigericin by an EDTA-ethanol treatment, which did not affect the assay when the ΔpH was not dissipated. The experiments were repeated at least three times and the results shown are representative.
