Fig. 4.

Evaluation of c_i 's redox behavior. (A) Redox-induced EPR difference spectra of the high-spin heme signals of the isolated b₆f complex from C. reinhardtii in the presence of 66 μM NQNO are shown; HP is +414/+200 mV; LP is −217/−337 mV. EPR settings are as for Fig. 1. (B) Signal amplitudes are plotted versus ambient redox potential: ■, g_y signal at 5.5; □, difference of the amplitudes of the g_x signals at 6.5 and 6.1. Two n = 1 Nernst curves were fitted to each set of data points. Asterisks indicate signal amplitude of the g_y signal at 5.32 from the titration without inhibitor versus ambient redox potential.