The pathway of cyclic electron transport in chromatophores of Chromatium vinosum. Evidence for a Q-cycle mechanism

Coremans, J. M. C. C.; Wal, H. N. Van Der; Grondelle, Rienk van; Amesz, J.; Knaff, David B.

doi:10.1016/0005-2728(85)90116-1

Cited by 20 publications

(13 citation statements)

References 31 publications

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“…Concerning the resistance to myxothiazol and antimycin, our results are different from the previous ones obtained with A. vinosum membranes (6,11,44). In the work of Tan et al (44) cyt c reductase activity was measurable only after a treatment with dodecyl maltoside detergent.…”

Section: Resultscontrasting

confidence: 98%

“…The resistance of both species to stigmatellin could be correlated to the E303V substitution in the cyt b subunit. Nevertheless, part of these results are different from previously published results for A. vinosum chromatophores that showed inhibition of the cyt bc 1 complex by both antimycin and myxothiazol (6,11,44). However, in this paper, we have measured resistance to inhibitors and identified the sequence flanking the PVWY loop on the same strain to get reliable results.…”

Section: Discussioncontrasting

confidence: 74%

“…The amount of cyt bc 1 complex was estimated by determining the cyt b concentration at 562 nm from the absorption difference spectra for the membrane suspension (dithionite minus ascorbate); ⌬ε [562 to 575 nm] ϭ 28 mM Ϫ1 cm Ϫ1 ) (11). Alternatively, the amount of cyt b was estimated by the pyridine hemochrome method (5) for B. viridis, R. gelatinosus, and A. vinosum.…”

Section: Methodsmentioning

confidence: 99%

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Natural Resistance to Inhibitors of the Ubiquinol Cytochrome c Oxidoreductase of Rubrivivax gelatinosus : Sequence and Functional Analysis of the Cytochrome bc ₁ Complex

2002

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Biochemical analyses of Rubrivivax gelatinosus membranes have revealed that the cytochrome bc 1 complex is highly resistant to classical inhibitors including myxothiazol, stigmatellin, and antimycin. This is the first report of a strain exhibiting resistance to inhibitors of both catalytic Q 0 and Q i sites. Because the resistance to cytochrome bc 1 inhibitors is primarily related to the cytochrome b primary structure, the petABC operon encoding the subunits of the cytochrome bc 1 complex of Rubrivivax gelatinosus was sequenced. In addition to homologies to the corresponding proteins from other organisms, the deduced amino acid sequence of the cytochrome b polypeptide shows (i) an E303V substitution in the highly conserved PEWY loop involved in quinol/stigmatellin binding, (ii) other substitutions that could be involved in resistance to cytochrome bc 1 inhibitors, and (iii) 14 residues instead of 13 between the histidines in helix IV that likely serve as the second axial ligand to the b H and b L hemes, respectively. These characteristics imply different functional properties of the cytochrome bc 1 complex of this bacterium. The consequences of these structural features for the resistance to inhibitors and for the properties of R. gelatinosus cytochrome bc 1 are discussed with reference to the structure and function of the cytochrome bc 1 complexes from other organisms.Ubihydroquinone cytochrome c oxidoreductase (cyt bc 1 complex) is an integral membrane complex involved in energy transduction in a wide range of organisms. Anoxygenic photosynthetic bacteria contain a cyt bc 1 complex, which serves for both light-driven electron transfer and dark respiration. For Rhodobacter sphaeroides and Rhodobacter capsulatus this enzyme catalyzes electron transfer from ubiquinol to soluble ferricytochrome c coupled to proton translocation across the membrane, thus generating an electrochemical gradient used for ATP synthesis. Oxygenic photosynthetic organisms contain a similar complex, i.e., cyt b 6f , which functions as a plastoquinol plastocyanin oxidoreductase (12). Structural and functional similarities have been reported for both types of cyt bc (3, 9, 41). The cyt bc complex was found to be made up of at least three subunits: cyt b (or b 6 ), containing the two b-type hemes of low (b L ) and high (b H ) redox potentials, cyt c 1 (or f) containing a c-type heme, and the Rieske protein (ISP) containing the [2Fe-2S] cluster. In addition to subunits containing the prosthetic groups and cofactors, the mitochondrial cyt bc 1 complex contains other subunits (4,29,30,46,47).Photosynthesis and aerobic respiration are affected by inhibitors. Some of these molecules are specific to the cyt bc complex. In fact, in many species the ubiquinol-cyt c oxidoreductase activity was found to be sensitive to quinone analogs such as myxothiazol, stigmatellin, antimycin, hydroxyquinoline Noxide (HQNO), and diuron. Extensive kinetic and genetic studies (7,13,16,17,19,28) as well as recent structural data available from X-ray crystallography of...

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Section: Resultscontrasting

confidence: 98%

Section: Discussioncontrasting

confidence: 74%

Section: Methodsmentioning

confidence: 99%

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Natural Resistance to Inhibitors of the Ubiquinol Cytochrome c Oxidoreductase of Rubrivivax gelatinosus : Sequence and Functional Analysis of the Cytochrome bc ₁ Complex

2002

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“…+ 200mV) components. The difference spectra both reveal the presence of a component with absorbance maxima (a-band = 553nm and /3-band = 523-524nm) consistent with the presence of cytochrome cl [18,10,17,9,15,42,32] in both the Rps. virMis and R. rubrurn complexes.…”

Section: Methodsmentioning

confidence: 68%

“…It has recently become clear that the membrane-bound electron transfer chains of mitochondria, chloroplasts, cyanobacteria and bacteriochlorophyll a-containing photosynthetic bacteria contain similar multi-peptide complexes that catalyze electron flow from quinol to a soluble cytochrome c or its functional equivalent, the copper-containing protein plastocyanin [18,10,17,9]. This complex contains cytochrome ci, two b cytochromes and the Rieske iron-sulfur protein.…”

Section: Introductionmentioning

confidence: 99%

Isolation of cytochrome bc 1 complexes from the photosynthetic bacteria Rhodopseudomonas viridis and Rhodospirillum rubrum

et al. 1986

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Cytochrome bc 1 complexes have been isolated from wild type Rhodopseudomonas viridis and Rhodospirillum rubrum and purified by affinity chromatography on cytochrome c-Sepharose 4B. Both complexes are largely free of bacteriochlorophyll and carotenoids and contain cytochromes b and c 1 in a 2:1 molar ratio. For the Rps. viridis complex, evidence has been obtained for two spectrally distinct b-cytochromes. The R. rubrum complex contains a Rieske iron-sulfur protein (present in approximately 1:1 molar ratio to cytochrome c 1) and catalyzes an antimycin A- and myxothiazol-sensitive electron transfer from duroquinol to equine cytochrome c or R. rubrum cytochrome c 2. Although an attempt to prepare a cytochrome bc 1 complex from the gliding green bacterium Chloroflexus aurantiacus was not successful, membranes isolated from phototrophically grown Cfl. aurantiacus were shown to contain a Rieske iron-sulfur protein and protoheme (the prosthetic group of b-type cytochromes).

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Cytochromes, Iron-Sulfur, and Copper Proteins Mediating Electron Transfer from the Cyt bc1 Complex to Photosynthetic Reaction Center Complexes

Meyer

Donohue

Advances in Photosynthesis and Respiration

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The pathway of cyclic electron transport in chromatophores of Chromatium vinosum. Evidence for a Q-cycle mechanism

Cited by 20 publications

References 31 publications

Natural Resistance to Inhibitors of the Ubiquinol Cytochrome c Oxidoreductase of Rubrivivax gelatinosus : Sequence and Functional Analysis of the Cytochrome bc ₁ Complex

Natural Resistance to Inhibitors of the Ubiquinol Cytochrome c Oxidoreductase of Rubrivivax gelatinosus : Sequence and Functional Analysis of the Cytochrome bc ₁ Complex

Isolation of cytochrome bc 1 complexes from the photosynthetic bacteria Rhodopseudomonas viridis and Rhodospirillum rubrum

Cytochromes, Iron-Sulfur, and Copper Proteins Mediating Electron Transfer from the Cyt bc1 Complex to Photosynthetic Reaction Center Complexes

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The pathway of cyclic electron transport in chromatophores of Chromatium vinosum. Evidence for a Q-cycle mechanism

Cited by 20 publications

References 31 publications

Natural Resistance to Inhibitors of the Ubiquinol Cytochrome c Oxidoreductase of Rubrivivax gelatinosus : Sequence and Functional Analysis of the Cytochrome bc 1 Complex

Natural Resistance to Inhibitors of the Ubiquinol Cytochrome c Oxidoreductase of Rubrivivax gelatinosus : Sequence and Functional Analysis of the Cytochrome bc 1 Complex

Isolation of cytochrome bc 1 complexes from the photosynthetic bacteria Rhodopseudomonas viridis and Rhodospirillum rubrum

Cytochromes, Iron-Sulfur, and Copper Proteins Mediating Electron Transfer from the Cyt bc1 Complex to Photosynthetic Reaction Center Complexes

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Product

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Natural Resistance to Inhibitors of the Ubiquinol Cytochrome c Oxidoreductase of Rubrivivax gelatinosus : Sequence and Functional Analysis of the Cytochrome bc ₁ Complex

Natural Resistance to Inhibitors of the Ubiquinol Cytochrome c Oxidoreductase of Rubrivivax gelatinosus : Sequence and Functional Analysis of the Cytochrome bc ₁ Complex