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Rieske's Iron Sulfur Protein

Structure of a water soluble fragment of the 'Rieske' iron-sulfur protein of the bovine heart mitochondrial cytochrome bc1 complex determined by MAD phasing at 1.5 Å resolution

Highlight groups of interest

• Leucine 142. "In Rb. capsulatus, mutation of this residue (Leu136 ) to glycine, asparagine, histidine or arginine completely blocked quinone binding, although the structure and the redox potential were apparently unperturbed (2)". Daladal and colleagues are studying additional mutations at this site.
• Glycine 143. "Gatti et al. [28] have identified three mutants in which the midpoint potential (Em) of the [2Fe-2S] cluster was altered: Gly143Asp (Em = -96 mV), Pro146Leu (Em = -98 mV), and Pro159Leu (Em = -53 mV)." Van Doren et al. have shown that the mutation equivalent to G143D showed a modified kinetics of quinol oxidation in Rb. sphaeroides (3); we are currently studying an extensive range of additional mutations at this position.
• Tyrosine 165. "Two OH-S hydrogen bonds are observed: S-1-Ser163 O and Cys139 S-Tyr165 O. Both Ser163 and Tyr165 are conserved in all known bc1 Rieske iron-sulfur proteins and should be important for the properties of the metal center; mutations in either residue led to a complete loss of the cluster" (4, 5). The Crofts and Trumpower labs are currently studying an extensive range of mutations at the position equivalent to 165 in Rb. sphaeroides and yeast respectively.

Reference

1. Iwata, S., Saynovits, M., Link, T.A. and Michel, H. (1996) Structure of a water soluble fragment of the 'Rieske' iron-sulfur protein of the bovine heart mitochondrial cytochrome bc1 complex determined by MAD phasing at 1.5 Å resolution. Structure 1996, 4: 567-579.
2. Liebl U., Sled V., Ohnishi T., Daldal F. (1995). Conserved non liganding residues of Rhodobacter (R.) capsulatus 'Rieske' protein are essential for [2Fe-2S] cluster properties and communication with the quinone pool. In Photosynthesis: from Light to Biosphere. (Mathis, P., eds.) II : 749-752. Kluwer Academic Publishers, Dordrecht.
3. Van Doren S.R., Gennis R.B., Barquera B., Crofts A.R. (1993). Site-directed mutations of conserved residues of the Rieske iron-sulfur subunit of the cytochrome bc₁ complex of Rhodobacter sphaeroides blocking or impairing quinol oxidation. Biochemistry 32 : 8083-8091
4. Gatti D.L., Meinhardt S.W., Ohnishi T., Tzagoloff A. (1989). Structure and function of the mitochondrial bc1 complex. A mutational analysis of the yeast Rieske iron-sulfur protein. J. Mol. Biol. 205 : 421-435.
5. Graham L.A., Brandt U., Sargent J.S., Trumpower B.L. (1992). Mutational analysis of assembly and function of the iron-sulfur protein of the cytochrome bc1 complex in Saccharomyces cerevisiae. J. Bioenerg. Biomembr. 25 : 245-257.