Energy transduction by respiratory metallo-enzymes: From molecular mechanism to cell physiology

Al-Attar, Sinan; Vries, Simon de

doi:10.1016/j.ccr.2012.05.022

Cited by 26 publications

(29 citation statements)

References 262 publications

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“…Cytochrome bd has long been considered a hetero-dimer throughout literature12320. However, recent mutational studies in E. coli, Brucella abortus and Shewanella oneidensis suggested that the small protein, CydX (37, 64 and 38 amino acids in E. coli, B. abortus and S. oneidensis , resp.)…”

Section: Resultsmentioning

confidence: 99%

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Cytochrome bd Displays Significant Quinol Peroxidase Activity

Al-Attar

Pinkse

et al. 2016

Sci Rep

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Cytochrome bd is a prokaryotic terminal oxidase that catalyses the electrogenic reduction of oxygen to water using ubiquinol as electron donor. Cytochrome bd is a tri-haem integral membrane enzyme carrying a low-spin haem b558, and two high-spin haems: b595 and d. Here we show that besides its oxidase activity, cytochrome bd from Escherichia coli is a genuine quinol peroxidase (QPO) that reduces hydrogen peroxide to water. The highly active and pure enzyme preparation used in this study did not display the catalase activity recently reported for E. coli cytochrome bd. To our knowledge, cytochrome bd is the first membrane-bound quinol peroxidase detected in E. coli. The observation that cytochrome bd is a quinol peroxidase, can provide a biochemical basis for its role in detoxification of hydrogen peroxide and may explain the frequent findings reported in the literature that indicate increased sensitivity to hydrogen peroxide and decreased virulence in mutants that lack the enzyme.

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Section: Resultsmentioning

confidence: 99%

“…The bioenergetic efficiency of cytochrome bd is half that of the oxygen-reducing cytochrome oxidases, which in addition to consuming chemical protons also pump protons across the membrane (reviewed in20). …”

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confidence: 99%

Cytochrome bd Displays Significant Quinol Peroxidase Activity

Al-Attar

Pinkse

et al. 2016

Sci Rep

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“…Instead, the cytochrome bc complexes are particularly fine-tuned to minimize the electron escape to oxygen in center P [120, 155]. Specifically, the lifetime of the semiquinone in center P is kept very short, so that that this semiquinone could be measured only under very special, steady state conditions [3]. However, when the oxidation of cytochrome b via center N is blocked, which can happen in the presence of inhibitors, or under the backpressure of membrane potential, or as a result of a conformational distortion of the bc 1 , or in response to an abrupt change in the redox balance of the ET chain, the probability of ubisemiquinone in center P could transiently increase, so that electrons can occasionally escape to oxygen yielding superoxide and other ROS [120, 155–159].…”

Section: Evolution Of Apoptosis As a Strategy To Diminish The Oxygmentioning

confidence: 99%

Evolution of cytochrome bc complexes: From membrane-anchored dehydrogenases of ancient bacteria to triggers of apoptosis in vertebrates

Dibrova

Cherepanov

Galperin

et al. 2013

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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This review traces the evolution of the cytochrome bc complexes from their early spread among prokaryotic lineages and up to the mitochondrial cytochrome bc1 complex (complex III) and its role in apoptosis. The results of phylogenomic analysis suggest that the bacterial cytochrome b6f-type complexes with short cytochromes b were the ancient form that preceded in evolution the cytochrome bc1-type complexes with long cytochromes b. The common ancestor of the b6f-type and the bc1-type complexes probably resembled the b6f-type complexes found in Heliobacteriaceae and in some Planctomycetes. Lateral transfers of cytochrome bc operons could account for the several instances of acquisition of different types of bacterial cytochrome bc complexes by archaea. The gradual oxygenation of the atmosphere could be the key evolutionary factor that has driven further divergence and spread of the cytochrome bc complexes. On one hand, oxygen could be used as a very efficient terminal electron acceptor. On the other hand, auto-oxidation of the components of the bc complex results in the generation of reactive oxygen species (ROS), which necessitated diverse adaptations of the b6f-type and bc1-type complexes, as well as other, functionally coupled proteins. A detailed scenario of the gradual involvement of the cardiolipin-containing mitochondrial cytochrome bc1 complex into the intrinsic apoptotic pathway is proposed, where the functioning of the complex as an apoptotic trigger is viewed as a way to accelerate the elimination of the cells with irreparably damaged, ROS-producing mitochondria.

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“…Within the protein, electrons travel through the redox cofactors (like hemes or iron-sulfur clusters) that form chains connecting various catalytic sites (4,183). The cofactor chains and catalytic sites of respiratory complexes are linked together by small electron carriers that move between complexes.…”

Section: Introductionmentioning

confidence: 99%

Electronic Connection Between the Quinone and CytochromecRedox Pools and Its Role in Regulation of Mitochondrial Electron Transport and Redox Signaling

Sarewicz

Osyczka

2015

Physiological Reviews

136

141

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Physiol Rev 95: 219 -243, 2015; doi:10.1152/physrev.00006.2014.-Mitochondrial respiration, an important bioenergetic process, relies on operation of four membranous enzymatic complexes linked functionally by mobile, freely diffusible elements: quinone molecules in the membrane and water-soluble cytochromes c in the intermembrane space. One of the mitochondrial complexes, complex III (cytochrome bc 1 or ubiquinol: cytochrome c oxidoreductase), provides an electronic connection between these two diffusible redox pools linking in a fully reversible manner two-electron quinone oxidation/reduction with one-electron cytochrome c reduction/oxidation. Several features of this homodimeric enzyme implicate that in addition to its well-defined function of contributing to generation of proton-motive force, cytochrome bc 1 may be a physiologically important point of regulation of electron flow acting as a sensor of the redox state of mitochondria that actively responds to changes in bioenergetic conditions. These features include the following: the opposing redox reactions at quinone catalytic sites located on the opposite sides of the membrane, the inter-monomer electronic connection that functionally links four quinone binding sites of a dimer into an H-shaped electron transfer system, as well as the potential to generate superoxide and release it to the intermembrane space where it can be engaged in redox signaling pathways. Here we highlight recent advances in understanding how cytochrome bc 1 may accomplish this regulatory physiological function, what is known and remains unknown about catalytic and side reactions within the quinone binding sites and electron transfers through the cofactor chains connecting those sites with the substrate redox pools. We also discuss the developed molecular mechanisms in the context of physiology of mitochondria.

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Energy transduction by respiratory metallo-enzymes: From molecular mechanism to cell physiology

Cited by 26 publications

References 262 publications

Cytochrome bd Displays Significant Quinol Peroxidase Activity

Cytochrome bd Displays Significant Quinol Peroxidase Activity

Evolution of cytochrome bc complexes: From membrane-anchored dehydrogenases of ancient bacteria to triggers of apoptosis in vertebrates

Electronic Connection Between the Quinone and CytochromecRedox Pools and Its Role in Regulation of Mitochondrial Electron Transport and Redox Signaling

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