Fig. 1.
pH change of the aqueous contents of M2PLs in response to the induction of a pH gradient induced at time = 0. Initial interior pH = 7 in all traces; external pH from top to bottom: pHout = 6.8, 6.5, 6.0, 5.5, 5.0. (A) Symmetrical [K+]in = [K+]out = 0.13 M, valinomycin present. (B) Symmetrical [K+]in = [K+]out = 0.13 M, no valinomycin. (C) Symmetrical [Na+]in = [Na+]out = 0.13 M, no valinomycin. These data are displayed as proton flux per tetramer in Fig. S1. Dotted (top) line of 1 B: Response of protein-free liposomes containing the protonophore CCCP but no valinomycin to a pH gradient of 1 pH unit induced at time = 0. (Trace offset -0.1 pH unit for clarity. The lower noise level of this trace is due to higher Glu3 concentration).