Studies on Inhibition of Respiratory Cytochrome bc1 Complex by the Fungicide Pyrimorph Suggest a Novel Inhibitory Mechanism
Figure 3
Difference spectra of inhibitors and inhibitors combinations to reduced Btbc1.
All spectra were recorded with purified Btbc1 at a concentration of 5 μM of cyt b with the concentrations of inhibitor as indicated. Prior to spectral scan, the bc1 complex was reduced by addition of dithionite. (A) Spectrum of reduced Btbc1 in the presence of 1 mM pyrimorph (pyr) minus that of reduced Btbc1 alone. (B) Spectrum of reduced Btbc1 in the presence of 10 μM myxothiazol (myx) minus that of reduced Btbc1 alone. (C) and (D) The spectrum of reduced Btbc1 in equilibration with 1 mM pyrimorph followed by addition of 10 μM myxothiazol minus spectrum of reduced Btbc1 in the presence of 10 μM myxothiazol or 1 mM pyrimorph, respectively. (E) Spectrum of reduced Btbc1 in the presence of 10 μM antimycin A (ant) minus spectrum of reduced Btbc1 alone. (F) Spectrum of reduced Btbc1 after equilibration with 1 mM pyrimorph and 10 μM antimycin A in sequence minus spectrum of reduced Btbc1 in the presence of antimycin A.