Fig. 3
From: The structural basis of proton driven zinc transport by ZntB
Radioactive and fluorescent transport assays (a) 65Zn2+ uptake via ZntB reconstituted in liposomes under different conditions (colour-coded: black—inward pH flux (7.5 in/6.5 out); green—outward pH flux (6.5 in/7.5 out); red and blue—no pH flux at 6.5 and 7.5 pH, respectively). Ionophore FCCP was added at the time point of 10 min. Note the opposite effect of FCCP on direct and reverse pH gradient. Error bars represent s.e.m. from more than three technical replicates of independent batches of proteoliposomes. b Changes in fluorescent signal by the reporter dye FluoZin-1 during uptake of Zn2+ (added at 1 min time point) via ZntB reconstituted in liposomes under different conditions (colour-coding as in a, additionally the signal from empty liposomes in magenta). FCCP was added at the time point of 6 min. Error bars represent s.e.m. from more than three technical replicates of independent batches of proteoliposomes. c Zn2+-dependent transport of H+ via ZntB. Quenching of the pH-dependent fluorophore ACMA at different Zn2+ concentrations is shown by unique colours. d Rate of transport dependence on Zn2+ concentration. The solid line represents the fit to the Michaelis–Menten equation with a K M of ~7.5 µM (based on FluoZin-1 experiments)
