[Cytochrome b-c1 complex subunit Rieske, mitochondrial]: Component of the ubiquinolcytochrome
c oxidoreductase, a multisubunit transmembrane complex that is part of the
mitochondrial electron transport chain which drives oxidative phosphorylation. The
respiratory chain contains 3 multisubunit complexes succinate dehydrogenase (complex
II, CII, ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III,
CIII and cytochrome c oxidase (complex IV, CIV, that cooperate to transfer electrons
derived from NADH and succinate to molecular oxygen, creating an electrochemical
gradient over the inner membrane that drives transmembrane transport and the ATP
synthase. The cytochrome b-c1 complex catalyzes electron transfer from ubiquinol to
cytochrome c, linking this redox reaction to translocation of protons across the
mitochondrial inner membrane, with protons being carried across the membrane as
hydrogens on the quinol. In the process called Q cycle, 2 protons are consumed from the
matrix, 4 protons are released into the intermembrane space and 2 electrons are passed
to cytochrome c. The Rieske protein is a catalytic core subunit containing a [2Fe-2S] ironsulfur
cluster. It cycles between 2 conformational states during catalysis to transfer
electrons from the quinol bound in the Q(0 site in cytochrome b to cytochrome c1 (By similarity. Incorporation of UQCRFS1 is the penultimate step in complex III assembly.