Proton-translocation by membrane-bound NADH:ubiquinone-oxidoreductase (complex I) through redox-gated ligand conduction

Brandt, Ulrich

doi:10.1016/s0005-2728(96)00141-7

Cited by 204 publications

(110 citation statements)

References 63 publications

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“…The degree of overlap between putative inhibition sites (or modes of inhibition), displayed as A, B, and C (25, 27), is not well understood. The coupling mechanism of complex I is not known, and we do not attempt to include proton translocation steps in our model; however, it does bear resemblance to aspects of other proposed models (29,30). During forward electron transport, electrons from NADH are passed to Q in a quinone-reducing site via the flavin (FMN) and iron sulfur centers.…”

Section: Figmentioning

confidence: 99%

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Inhibitors of the Quinone-binding Site Allow Rapid Superoxide Production from Mitochondrial NADH:Ubiquinone Oxidoreductase (Complex I)

Lambert

Brand

2004

Journal of Biological Chemistry

430

344

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Neither the route of electron transport nor the sites or mechanism of superoxide production in mitochondrial complex I has been established. We examined the rates of superoxide generation (measured as hydrogen peroxide production) by rat skeletal muscle mitochondria under a variety of conditions. The rate of superoxide production by complex I during NADH-linked forward electron transport was less than 10% of that during succinate-linked reverse electron transport even when complex I was fully reduced by pyruvate plus malate in the presence of the complex III inhibitor, stigmatellin. This asymmetry was not explained by differences in protonmotive force or its components. However, when inhibitors of the quinone-binding site of complex I were added in the presence of ATP to generate a pH gradient, there was a rapid rate of superoxide production by forward electron transport that was as great as the rate seen with reverse electron transport at the same pH gradient. These observations suggest that quinone-binding site inhibitors can make complex I adopt the highly radical-producing state that occurs during reverse electron transport. Despite complete inhibition of NADH: ubiquinone oxidoreductase activity in each case, different classes of quinone-binding site inhibitor (rotenone, piericidin, and high concentrations of myxothiazol) gave different rates of superoxide production during forward electron transport (the rate with myxothiazol was twice that with rotenone) suggesting that the site of rapid superoxide generation by complex I is in the region of the ubisemiquinone-binding sites and not upstream at the flavin or low potential FeS centers.

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Section: Figmentioning

confidence: 99%

“…The coupling mechanism of complex I remains unknown, but analogies to the Q cycle in complex III have been proposed (29). Other models have been suggested that are consistent with Q cycle-type behavior in the enzyme (30).…”

Section: Figmentioning

confidence: 99%

Inhibitors of the Quinone-binding Site Allow Rapid Superoxide Production from Mitochondrial NADH:Ubiquinone Oxidoreductase (Complex I)

Lambert

Brand

2004

Journal of Biological Chemistry

430

344

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“…(27) and (28) observed in Range A, the product in DCE (CQ •¹ ) transfers to W at E in Range A2 (curve 2 in Fig. 3) since CQ •¹ has a charge.…”

Section: 1′mentioning

confidence: 74%

Biomimetic Charge Transfer Reactions at the Aqueous/Organic Solution Interface or through Artificial Membrane

et al. 2012

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Some biomimetic reactions observed with the aid of aqueous/organic, W/O, two phases or liquid membrane, LM, systems were introduced. The reactions introduced were mostly those reported by the group of present authors as follows; (1) (5) A new type of membrane transport reaction realized in the presence of an applied electrical potential gradient parallel to the W/ membrane interface. The processes of above-described reactions were elucidated based on the voltammetric methods and concepts taking into account the properties common to both artificial LMs and biomembranes. A method proposed by present authors for the elucidation of the membrane transport process was also introduced.

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“…Over the past decades different mechanisms have been proposed, several of which may now be excluded based on the recently available structural data on complex I, namely those suggesting the direct involve- (29) or of the iron-sulfur center N2 (30). In addition, models describing H 1 translocation directly linked to the quinone/quinol couple are no longer consensually considered (31).…”

Section: Ion/electron Coupling Mechanism In Complex Imentioning

confidence: 99%

The role of proton and sodium ions in energy transduction by respiratory complex I

2012

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SummaryRespiratory complex I plays a central role in energy transduction. It catalyzes the oxidation of NADH and the reduction of quinone, coupled to cation translocation across the membrane, thereby establishing an electrochemical potential. For more than half a century, data on complex I has been gathered, including recently determined crystal structures, yet complex I is the least understood complex of the respiratory chain. The mechanisms of quinone reduction, charge translocation and their coupling are still unknown. The H 1 is accepted to be the coupling ion of the system; however, Na 1 has also been suggested to perform such a role. In this article, we address the relation of those two ions with complex I and refer ion pump and Na 1 /H 1 antiporter as possible transport mechanisms of the system. We put forward a hypothesis to explain some apparently contradictory data on the nature of the coupling ion, and we revisit the role of H 1 and Na 1 cycles in the overall bioenergetics of the cell. IUBMBIUBMB Life, 64(6): 492-498, 2012

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Proton-translocation by membrane-bound NADH:ubiquinone-oxidoreductase (complex I) through redox-gated ligand conduction

Cited by 204 publications

References 63 publications

Inhibitors of the Quinone-binding Site Allow Rapid Superoxide Production from Mitochondrial NADH:Ubiquinone Oxidoreductase (Complex I)

Inhibitors of the Quinone-binding Site Allow Rapid Superoxide Production from Mitochondrial NADH:Ubiquinone Oxidoreductase (Complex I)

Biomimetic Charge Transfer Reactions at the Aqueous/Organic Solution Interface or through Artificial Membrane

The role of proton and sodium ions in energy transduction by respiratory complex I

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