Fig. 5

Change of the fluorescence intensity of a pH-sensitive dye (pyranine) during the photocycle of the RC. Fluorescence increase indicates pH increase inside the liposomes. Light is switched on and off, as indicated by the arrows. The effect of the protonophore gramicidin (gram) is also shown. Insert: Schematic representation of the RC turnover photocycle. Upon excitation by light P/P⁺//Q/Q- redox pair is created. The P/P⁺ couple is connected to cytochrome c2⁺/ cytochrome c3⁺ turnover on the donor side. The acceptor side is reset by the release of doubly reduced (and protonated) quinone and binding of the oxidized one to the RC. During the whole photocycle DpH is created