STUDIES ON THE ORIENTATIONS OF THE MITOCHONDRIAL REDOX CARRIERS - ORIENTATION OF THE CHROMOPHORES OF CYTOCHROME-B-C1 COMPLEX WITH RESPECT TO THE PLANE OF A CYTOCHROME-B-C1 COMPLEX LIPID MODEL MEMBRANE

Orientations of the active site chromophores of the pig heart muscle mitochondrial cytochrome b-c1 complex incorporated into liposomes have been investigated in hydrated oriented multilayers of proteoliposome membranes using optical and EPR spectroscopy. The hemes of cytochromes c1 and b were oriented with the normal to their heme planes lying approximately in the plane of the proteoliposome membrane. Rieske''s Fe S center was oriented with the z-axis of the g tensor parallel to the plane of the membranes. The cytochrome b-c1 complex has a structural asymmetry which causes it to orient with respect to the lipid bilayer.