The circular-dichroic properties of the 'Rieske' iron-sulphur protein in the mitochondrial ubiquinol: cytochrome c reductase.

Changes to the length of the flexible linker region of the Rieske protein impair the interaction of ubiquinol with the cytochrome bc1 complex.

Crystal structures of the cytochrome bc1 complex indicate that the catalytic domain of the Rieske iron-sulfur protein, which carries the [2Fe-2S] cluster, is connected to a transmembrane anchor by a flexible linker region. This flexible linker allows the catalytic domain to move between two positions, proximal to cytochrome b and cytochrome c1. Addition of an alanine residue to the flexible lin...

Role of the Rieske iron-sulfur protein midpoint potential in the protonmotive Q-cycle mechanism of the cytochrome bc1 complex.

The midpoint potential of the [2Fe-2S] cluster of the Rieske iron-sulfur protein (Em7 = +280 mV) is the primary determinant of the rate of electron transfer from ubiquinol to cytochrome c catalyzed by the cytochrome bc1 complex. As the midpoint potential of the Rieske cluster is lowered by altering the electronic environment surrounding the cluster, the ubiquinol-cytochrome c reductase activity...

Elimination of the disulfide bridge in the Rieske iron-sulfur protein allows assembly of the [2Fe-2S] cluster into the Rieske protein but damages the ubiquinol oxidation site in the cytochrome bc1 complex.

The [2Fe-2S] cluster of the Rieske iron-sulfur protein is held between two loops of the protein that are connected by a disulfide bridge. We have replaced the two cysteines that form the disulfide bridge in the Rieske protein of Saccharomyces cerevisiae with tyrosine and leucine, and tyrosine and valine, to evaluate the effects of the disulfide bridge on assembly, stability, and thermodynamic p...

Structure and function of the mitochondrial ubiquinol: cytochrome c reductase and NADH: ubiquinone reductase.

Structurc of' uhiquinol : cytochrome c reductase Ubiquinol : cytochrome c reductase (cytochrome reductase) from Neurospora crassa mitochondria is a dimer and the monomeric unit consists of nine different subunits. The subunits I and I I are known as core-proteins, I I I , IV and V are the cytochromes h, c , and the iron-sulphur protein, and VI to IX are small proteins without prosthetic groups ...

Topographical distribution of redox centres and the Qo site in ubiquinol-cytochrome-c oxidoreductase (complex III) and ligand structure of the Rieske iron-sulphur cluster.