The role of the `Rieske' iron sulfur protein in the hydroquinone oxidation (QP) site of the cytochrome bc 1 complex

@article{Link1997TheRO,
  title={The role of the `Rieske' iron sulfur protein in the hydroquinone oxidation (QP) site of the cytochrome bc
1 complex},
  author={T. A. Link},
  journal={FEBS Letters},
  year={1997},
  volume={412}
}
  • T. A. Link
  • Published 1997
  • Chemistry, Medicine
  • FEBS Letters
The essential reaction in the widely accepted protonmotive Q‐cycle mechanism of the bc 1 complex is the bifurcation of the electron flow during hydroquinone oxidation at the hydroquinone oxidation (QP) site formed by the `Rieske' iron sulfur protein and by the heme b L domain of cytochrome b. The `Rieske' [2Fe‐2S] cluster has a unique structure containing two exposed histidine ligands, which are the binding site for quinones. The affinity of the `Rieske' cluster for quinones increases several… Expand
Observations concerning the quinol oxidation site of the cytochrome bc 1 complex
A direct hydrogen bond between ubiquinone/quinol bound at the QO site and a cluster‐ligand histidine of the iron–sulfur protein (ISP) is described as a major determining factor explaining muchExpand
Similar Transition States Mediate the Q-cycle and Superoxide Production by the Cytochrome bc1 Complex*
TLDR
Three possible general models are tested to account for the behavior of the quinol oxidase site, where the rate-limiting step for both Q-cycle and superoxide production is essentially identical, consistent with model 1 but requiring modifications to models 2 and 3. Expand
pH-induced Intramolecular Electron Transfer between the Iron-Sulfur Protein and Cytochrome c 1 in Bovine Cytochrome bc 1 Complex*
TLDR
The results suggest that oxidized ISP has a higher mobility than reduced ISP and that the movement of reduced ISP may require an energy input from another component. Expand
Structural basis for the mechanism of electron bifurcation at the quinol oxidation site of the cytochrome bc1 complex
TLDR
Crystallographic binding studies of bc1 with either quinone reduction (QN) and/or quinol oxidation (QP) site inhibitors offer atomic details on how these compounds interact with residues at their respective sites suggest a mechanism for electron bifurcation at the QP site. Expand
The Iron-Sulfur Cluster of the Rieske Iron-Sulfur Protein Functions as a Proton-exiting Gate in the Cytochrome bc1 Complex*
TLDR
Results indicated that elimination of the [2Fe-2S] cluster in mutant bc1 complexes opened up an otherwise closed proton channel within the bc1 complex. Expand
Modifications of Protein Environment of the [2Fe-2S] Cluster of the bc1 Complex
TLDR
H-bonds to the cluster or its ligands are important determinants of the electrochemical characteristics of the ISP, likely through electron affinity of the interacting atom and the geometry of the H-bonding neighborhood, as well as the dependence of rate on driving force and pH. Expand
Energy transduction function of the quinone reactions in cytochrome bc complexes
TLDR
The modern biochemical refinements of the original chemiosmotic theory require electron and proton transfer from quinones to particular residues/redox centers of integral membrane proteins and subsequent transfer of H+ to the bulk aqueous phase outside the membrane. Expand
Pathways for proton release during ubihydroquinone oxidation by the bc(1) complex.
  • A. Crofts, S. Hong, +4 authors E. Berry
  • Chemistry, Medicine
  • Proceedings of the National Academy of Sciences of the United States of America
  • 1999
TLDR
From the structure of the stigmatellin-containing mitochondrial complex, it is suggested that hydrogen bonds to the two quinol hydroxyl groups help to stabilize the enzyme-substrate complex and aid proton release and that the carboxylate function is essential for rapid turnover. Expand
Electron Transfer Reactions at the Q o Site of the Cytochrome bc 1 Complex: The Good, the Bad, and the Ugly
The cytochrome bc1 complex of eukaryotic mitochondrial and prokaryotic energy transducing membranes functions as a protonmotive quinol:cytochrome c oxidoreductase. The enzyme utilizes a highlyExpand
A semiquinone intermediate generated at the Qo site of the cytochrome bc1 complex: Importance for the Q-cycle and superoxide production
TLDR
The first direct detection of a semiquinone radical generated by the Qo site is reported using continuous wave and pulsed EPR spectroscopy, suggesting that it is the elusive intermediate responsible for superoxide production. Expand
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 35 REFERENCES
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 A resolution.
TLDR
The high-resolution structure supports the proposed coordination pattern involving histidine ligands and provides a basis for a detailed analysis of the spectroscopic and electrochemical properties of the 'Rieske' [2Fe-2S] cluster. Expand
Evidence for a two proton dependent redox equilibrium in an archaeal Rieske iron-sulfur cluster.
TLDR
To the authors' knowledge, for the first time, in a membrane bound Rieske iron-sulfur protein, unequivocal evidence for a two proton dependent redox equilibrium is presented. Expand
Functional implications of the structure of the 'Rieske' iron-sulfur protein of bovine heart mitochondrial cytochrome bc1 complex.
TLDR
This is the first structure of a bis-histidine coordinated [2Fe-2S] cluster and the spectroscopic, electrochemical, and functional implications of the structure will be discussed. Expand
What information do inhibitors provide about the structure of the hydroquinone oxidation site of ubihydroquinone: Cytochromec oxidoreductase?
TLDR
The interactions with the protein segments, between differentprotein segments, and between protein and ligands (substrate, inhibitors) are discussed in detail and a working model of the QP pocket is proposed. Expand
Bifurcated ubihydroquinone oxidation in the cytochrome bc 1 complex by proton‐gated charge transfer
TLDR
A detailed model for the reactions during steady‐state catalysis is proposed based on a model of the ubihydroquinone‐oxidation pocket containing two ubiquinone molecules in a stacked configuration, and in this proton‐gated charge‐transfer mechanism the reaction is controlled by the deprotonation of the substrate Ubuntu. Expand
Significance of the "Rieske" iron-sulfur protein for formation and function of the ubiquinol-oxidation pocket of mitochondrial cytochrome c reductase (bc1 complex).
TLDR
The binding of specific inhibitors to the ubiquinol oxidation pocket ("QP center") of cytochrome c reductase was analyzed before and after removal of bound phospholipid and the "Rieske" iron-sulfur protein using optical spectroscopy and fluorescence quench binding assays to infer the stability of the two states is affected by the redox states of the enzyme. Expand
Ubiquinone pair in the Qo site central to the primary energy conversion reactions of cytochrome bc1 complex.
TLDR
Measurement of the yield and rate of QH2 oxidation generated by single turnover flashes in the family of mutants suggests that the Qos and Qow domains serve different roles for the catalytic process, with the yield correlated linearly with Qos domain occupancy (QH2 or Q), suggesting that theQos domain exchanges Q or Qh2 with the Qpool at a rate which is much slower than the time scale of turnover. Expand
Q-band ENDOR spectra of the Rieske protein from Rhodobactor capsulatus ubiquinol-cytochrome c oxidoreductase show two histidines coordinated to the [2Fe-2S] cluster.
Electron nuclear double resonance (ENDOR) experiments were performed on 14N (natural abundance) and 15N-enriched iron-sulfur Rieske protein in the ubiquinol-cytochrome c2 oxidoreductase fromExpand
The protonmotive Q cycle in mitochondria and bacteria.
TLDR
The Q cycle mechanism has been documented by extensive experimentation, and recent investigations have focused on structural features of the three redox subunits of the bc1 complex essential to the protonmotive and electrogenic activities of this membranous enzyme. Expand
How rapid are the internal reactions of the ubiquinol:cytochrome c2 oxidoreductase?
TLDR
The temperature dependence of the partial reactions leading to turn-over of the UQH2:cyt c2 oxidoreductase of Rhodobacter sphaeroides and the values for rate constants, stability constant, the redox potentials of the intermediate couples, and the binding constant for the semiquinone are discussed, which are pertinent to the mechanism of the ubiquinol oxidizing site. Expand
...
1
2
3
4
...