Energy-dependent Complex I-associated ubisemiquinones in submitochondrial particles
| Autor: | Andrei D. Vinogradov, I.A. Moroz, Dosymzhan Sh. Burbaev, Vladimir D. Sled, Tomoko Ohnishi, Vera G. Grivennikova |
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| Rok vydání: | 1995 |
| Předmět: |
Iron-Sulfur Proteins
Energy dependent Hot Temperature Energy-coupling Protein Conformation Ubiquinone NADH-ubiquinone oxidoreductase Submitochondrial Particles Coenzymes Biophysics Iron–sulfur cluster Carbonyl cyanide m-chlorophenyl hydrazone Photochemistry Biochemistry Mitochondria Heart Ubisemiquinone law.invention chemistry.chemical_compound Bovine heart submitochondrial particle Structural Biology law Rotenone NAD(P)H Dehydrogenase (Quinone) Genetics Animals Submitochondrial particle Electron paramagnetic resonance Spin (physics) Molecular Biology Coupling constant HEPES Electron Spin Resonance Spectroscopy Cell Biology Kinetics Crystallography EPR-spectroscopy chemistry Thermodynamics Cattle Iron-sulfur cluster Protein Binding |
| Zdroj: | FEBS Letters. 370:83-87 |
| ISSN: | 0014-5793 |
| Popis: | Two distinct species of Complex I-associated ubisemiquinones (SQNf and SQN,) were detected by cryogenic EPR analysis of tightly coupled submitochondrial particles oxi- dizing NADH or succinate under steady-state conditions. The g = 2.00 signals from both fast-relaxing SQNf (Pro -- 170 mW at 40 K) and slow-relaxing SQNs (Pro = 0.7 mW) are sensitive to uncouplers, rotenone and thermally induced deactivation of Com- plex I. At higher temperatures the SQN~ signal is broadened and only the SQN s signal is seen (Pu2 = 7 mW at 105 K). The spin- spin interaction between SQNf and the iron-sulfur cluster N2 was detected as split peaks of the gu 2.05 signal with a coupling constant of 1.65 mT, revealing their mutual distance of 8-11 A. The data obtained are consistent with a model in which N2 and two interacting bound ubisemiquinone species are spatially ar- ranged within the hydrophobic domain of Complex I, participat- ing in the vectorial proton translocation. |
| Databáze: | OpenAIRE |
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