Figure 2.

Testing the sensitivity of g = 1.94 and g = 2.0 signals to inhibitors and mutations that abolish the activity of the Q_o site. X-Band EPR spectra of isolated WT cytochrome bc₁ obtained under the conditions described for Figure 1c in the presence of antimycin alone (a) or antimycin and one of the Q_o site inhibitors: tridecyl-stigmatellin (b), atovaquone (c), famoxadone (d), myxothiazol (e), azoxystrobin (f), or kresoxim-methyl (g). Spectra of antimycin-inhibited mutants G158W (h) and the b-c₁ subcomplex (i). The left panel (FeS) shows spectra measured at 20 K in a magnetic field range of the FeS signal, and the right panel (SQ_o) shows spectra measured at 200 K in a magnetic field range typical of organic radicals.