e Also called cytochrome c reductase or cytochrome bCl complex e a250 kD multiprotein complex of ll subunits e Complete 3-D structure was determined in 1997 e The functional core consists of three subunits cytochrome b(with two hemes, bH and bu); an Fe-S protein; and cytochrome c,(with the heme group covalently bound to protein via two thioether bonds) e Two-electron carrier QH2 passes one electron to the one electron carrier Fe-S center, then to the heme C group in Cyt Cl, and finally to the heme c group of Cyt c, the SO-called "Q cycle Hs and finally to an Q or Q. via a other electron to b. b e Cytochrome c, a soluble protein located in the intermembrane space, will move to complex Iv Also called cytochrome c reductase or cytochrome bc1 complex.  A 250 kD multiprotein complex of 11 subunits.  Complete 3-D structure was determined in 1997!  The functional core consists of three subunits: cytochrome b (with two hemes, bH and bL ); an Fe-S protein; and cytochrome c1 (with the heme group covalently bound to protein via two thioether bonds).  Two-electron carrier QH2 passes one electron to the one￾electron carrier Fe-S center, then to the heme C group in Cyt c1 , and finally to the heme C group of Cyt c; the other electron to bL , bH, and finally to an Q or Q. - via a so-called “Q cycle”.  Cytochrome c, a soluble protein located in the intermembrane space, will move to complex IV