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Bridges HR, Bill E, Hirst J. Mössbauer spectroscopy on respiratory complex I: the iron-sulfur cluster ensemble in the NADH-reduced enzyme is partially oxidized. Biochemistry 2011; 51:149-58. [PMID: 22122402 PMCID: PMC3254188 DOI: 10.1021/bi201644x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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In mitochondria, complex I (NADH:quinone oxidoreductase)
couples
electron transfer to proton translocation across an energy-transducing
membrane. It contains a flavin mononucleotide to oxidize NADH, and
an unusually long series of iron–sulfur (FeS) clusters that
transfer the electrons to quinone. Understanding electron transfer
in complex I requires spectroscopic and structural data to be combined
to reveal the properties of individual clusters and of the ensemble.
EPR studies on complex I from Bos taurus have established
that five clusters (positions 1, 2, 3, 5, and 7 along the seven-cluster
chain extending from the flavin) are (at least partially) reduced
by NADH. The other three clusters, positions 4 and 6 plus a cluster
on the other side of the flavin, are not observed in EPR spectra from
the NADH-reduced enzyme: they may remain oxidized, have unusual or
coupled spin states, or their EPR signals may be too fast relaxing.
Here, we use Mössbauer spectroscopy on 57Fe-labeled
complex I from the mitochondria of Yarrowia lipolytica to show that the cluster ensemble is only partially reduced in the
NADH-reduced enzyme. The three EPR-silent clusters are oxidized, and
only the terminal 4Fe cluster (position 7) is fully reduced. Together
with the EPR analyses, our results reveal an alternating profile of
higher and lower potential clusters between the two active sites in
complex I; they are not consistent with the consensus picture of a
set of isopotential clusters. The implications for intramolecular
electron transfer along the extended chain of cofactors in complex
I are discussed.
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Affiliation(s)
- Hannah R Bridges
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Cambridge, CB2 0XY, UK
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2
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Tumanova LV, Tukhvatullin IA, Burbaev DS, Gvozdev RI, Andersson KK. The binuclear iron site of membrane-bound methane hydroxylase from Methylococcus capsulatus (Strain M). RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2011; 34:194-203. [DOI: 10.1134/s1068162008020064] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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3
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Abstract
Based on explicit definitions of biomolecular EPR spectroscopy and of the metallome, this tutorial review positions EPR in the field of metallomics as a unique method to study native, integrated systems of metallobiomolecular coordination complexes subject to external stimuli. The specific techniques of whole-system bioEPR spectroscopy are described and their historic, recent, and anticipated applications are discussed.
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Affiliation(s)
- Wilfred R Hagen
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, The Netherlands.
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4
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Ohnishi T, Ohnishi ST, Shinzawa-Ito K, Yoshikawa S. Functional role of coenzyme Q in the energy coupling of NADH-CoQ oxidoreductase (Complex I): stabilization of the semiquinone state with the application of inside-positive membrane potential to proteoliposomes. Biofactors 2008; 32:13-22. [PMID: 19096096 PMCID: PMC2683760 DOI: 10.1002/biof.5520320103] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Coenzyme Q10 (which is also designated as CoQ10, ubiquinone-10, UQ10, CoQ, UQ or simply as Q) plays an important role in energy metabolism. For NADH-Q oxidoreductase (complex I), Ohnishi and Salerno proposed a hypothesis that the proton pump is operated by the redox-driven conformational change of a Q-binding protein, and that the bound form of semiquinone (SQ) serves as its gate [FEBS Letters 579 (2005) 45-55]. This was based on the following experimental results: (i) EPR signals of the fast-relaxing SQ anion (designated as QNf(.-)) are observable only in the presence of the proton electrochemical potential (DeltamuH+); (ii) iron-sulfur cluster N2 and QNf(.-) are directly spin-coupled; and (iii) their center-to-center distance was calculated as 12angstroms, but QNf(.-) is only 5angstroms deeper than N2 perpendicularly to the membrane. After the priming reduction of Q to QNf(.-), the proton pump operates only in the steps between the semiquinone anion (QNf(.-)) and fully reduced quinone (QH2). Thus, by cycling twice for one NADH molecule, the pump transports 4H+ per 2e(-). This hypothesis predicts the following phenomena: (a) Coupled with the piericidin A sensitive NADH-DBQ or Q1 reductase reaction, DeltamuH+ would be established; (b) DeltamuH+ would enhance the SQ EPR signals; and (c) the dissipation of DeltamuH+ with the addition of an uncoupler would increase the rate of NADH oxidation and decrease the SQ signals. We reconstituted bovine heart complex I, which was prepared at Yoshikawa's laboratory, into proteoliposomes. Using this system, we succeeded in demonstrating that all of these phenomena actually took place. We believe that these results strongly support our hypothesis.
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Affiliation(s)
- Tomoko Ohnishi
- Dept of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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5
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Hirst J. Energy transduction by respiratory complex I--an evaluation of current knowledge. Biochem Soc Trans 2005; 33:525-9. [PMID: 15916556 DOI: 10.1042/bst0330525] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Complex I (NADH:ubiquinone oxidoreductase) is a membrane-bound, multisubunit enzyme. At present, there is no high-resolution structural model available for complex I and its mechanism of energy transduction is unknown. However, the subunit compositions of complex I from both eukaryotic and prokaryotic organisms have been determined, the sequences of their subunits are known and a coherent picture of the redox cofactors present in complex I has been developed. Here, I aim to describe and examine data relating to the mechanism of complex I and to build a framework to facilitate the discussion of possible conclusions and mechanistic models.
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Affiliation(s)
- J Hirst
- Medical Research Council Dunn Human Nutrition Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 2XY, UK.
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6
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Ohnishi T, Salerno JC. Conformation-driven and semiquinone-gated proton-pump mechanism in the NADH-ubiquinone oxidoreductase (complex I). FEBS Lett 2005; 579:4555-61. [PMID: 16098512 DOI: 10.1016/j.febslet.2005.06.086] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Accepted: 06/27/2005] [Indexed: 10/25/2022]
Abstract
A novel mechanism for proton/electron transfer is proposed for NADH-quinone oxidoreductase (complex I) based on the following findings: (1) EPR signals of the protein-bound fast-relaxing semiquinone anion radicals (abbreviated as Q(Nf)-) are observable only in the presence of proton-transmembrane electrochemical potential; (2) Iron-sulfur cluster N2 and Q(Nf)- are directly spin-coupled; and (3) The projection of the interspin vector extends only 5A along the membrane normal [Yano, T., Dunham, W.R. and Ohnishi, T. (2005) Biochemistry, 44, 1744-1754]. We propose that the proton pump is operated by redox-driven conformational changes of the quinone binding protein. In the input state, semiquinone is reduced to quinol, acquiring two protons from the N (matrix) side of the mitochondrial inner membrane and an electron from the low potential (NADH) side of the respiratory chain. A conformational change brings the protons into position for release at the P (inter-membrane space) side of the membrane via a proton-well. Concomitantly, an electron is donated to the quinone pool at the high potential side of the coupling site. The system then returns to the original state to repeat the cycle. This hypothesis provides a useful frame work for further investigation of the mechanism of proton translocation in complex I.
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Affiliation(s)
- Tomoko Ohnishi
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA.
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7
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Kushnareva Y, Murphy AN, Andreyev A. Complex I-mediated reactive oxygen species generation: modulation by cytochrome c and NAD(P)+ oxidation-reduction state. Biochem J 2002; 368:545-53. [PMID: 12180906 PMCID: PMC1222999 DOI: 10.1042/bj20021121] [Citation(s) in RCA: 501] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2002] [Accepted: 08/15/2002] [Indexed: 02/07/2023]
Abstract
Several lines of evidence indicate that mitochondrial reactive oxygen species (ROS) generation is the major source of oxidative stress in the cell. It has been shown that ROS production accompanies cytochrome c release in different apoptotic paradigms, but the site(s) of ROS production remain obscure. In the current study, we demonstrate that loss of cytochrome c by mitochondria oxidizing NAD(+)-linked substrates results in a dramatic increase of ROS production and respiratory inhibition. This increased ROS production can be mimicked by rotenone, a complex I inhibitor, as well as other chemical inhibitors of electron flow that act further downstream in the electron transport chain. The effects of cytochrome c depletion from mitoplasts on ROS production and respiration are reversible upon addition of exogenous cytochrome c. Thus in these models of mitochondrial injury, a primary site of ROS generation in both brain and heart mitochondria is proximal to the rotenone inhibitory site, rather than in complex III. ROS production at complex I is critically dependent upon a highly reduced state of the mitochondrial NAD(P)(+) pool and is achieved upon nearly complete inhibition of the respiratory chain. Redox clamp experiments using the acetoacetate/L-beta-hydroxybutyrate couple in the presence of a maximally inhibitory rotenone concentration suggest that the site is approx. 50 mV more electronegative than the NADH/NAD(+) couple. In the absence of inhibitors, this highly reduced state of mitochondria can be induced by reverse electron flow from succinate to NAD(+), accounting for profound ROS production in the presence of succinate. These results lead us to propose a model of thermodynamic control of mitochondrial ROS production which suggests that the ROS-generating site of complex I is the Fe-S centre N-1a.
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Affiliation(s)
- Yulia Kushnareva
- Mitochondrial Biology, MitoKor, 11494 Sorrento Valley Road, San Diego, CA 92024, U.S.A
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8
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Shifman JM, Moser CC, Kalsbeck WA, Bocian DF, Dutton PL. Functionalized de novo designed proteins: mechanism of proton coupling to oxidation/reduction in heme protein maquettes. Biochemistry 1998; 37:16815-27. [PMID: 9843452 DOI: 10.1021/bi9816857] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Proton exchange with aqueous media coupled to heme oxidation/reduction is commonly seen but not understood in natural cytochromes. Our synthetic tetrahelix bundle heme protein maquettes successfully reproduce natural proton coupling to heme oxidation/reduction. Potentiometry reveals major pK shifts from 4.2 to 7.0 and from 9.4 to 10.3 in the maquette-associated acid/base group(s) upon heme reduction. Consequently, a 210 mV decrease in the heme redox potential is observed between the two extremes of pH. Potentiometry with resonance Raman and FTIR spectroscopy performed over a wide pH range strongly implicates glutamate side chains as the source of proton coupling below pH 8.0, whereas lysine side chains are suggested above pH 8.0. Remarkably, the pK values of several glutamates in the maquette are elevated from their solution value (4.4) to values as high as 7.0. It is suggested that these glutamates are recruited into the interior of the bundle as part of a structural rearrangement that occurs upon heme binding. Glutamate to glutamine variants of the prototype protein demonstrate that removal of the glutamate closest to the heme diminishes but does not abolish proton exchange. It is necessary to remove additional glutamates before pH-independent heme oxidation/reduction profiles are achieved. The mechanism of redox-linked proton coupling appears to be rooted in distributed partial charge compensation, the magnitude of which is governed by the dielectric distance between the ferric heme and acid/base side chains. A similar mechanism is likely to exist in native redox proteins which undergo charge change upon cofactor oxidation/reduction.
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Affiliation(s)
- J M Shifman
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia 19104, USA
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9
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Dutton PL, Moser CC, Sled VD, Daldal F, Ohnishi T. A reductant-induced oxidation mechanism for complex I. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1364:245-57. [PMID: 9593917 DOI: 10.1016/s0005-2728(98)00031-0] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A model for energy conversion in Complex I is proposed that is a conservative expansion of Mitchell's Q-cycle using a simple mechanistic variation of that already established experimentally for Complex III. The model accommodates the following proposals. (1) The large number of flavin and iron-sulfur redox cofactors integral to Complex I form a simple but long electron transfer chain guiding submillisecond electron transfer from substrate NADH in the matrix to the [4Fe-4S] cluster N2 close to the matrix-membrane interface. (2) The reduced N2 cluster injects a single electron into a ubiquinone (Q) drawn from the membrane pool into a nearby Qnz site, generating an unstable transition state semiquinone (SQ). The generation of a SQ species is the primary step in the energy conversion process in Complex I, as in Complex III. In Complex III, the SQ at the Qo site near the cytosolic side acts as a strong reductant to drive electronic charge across the membrane profile via two hemes B to a Qi site near the matrix side. We propose that in Complex I, the SQ at the Qnz site near the matrix side acts as a strong oxidant to pull electronic charge across the membrane profile via a quinone (Qny site) from a Qnx site near the cytosolic side. The opposing locations of matrix side Qnz and cytosolic side Qo, together with the opposite action of Qnz as an oxidant rather than a reductant, renders the Complex I and III processes vectorially and energetically complementary. The redox properties of the Qnz and Qo site occupants can be identical. (3) The intervening Qny site of Complex I acts as a proton pumping element (akin to the proton pump of Complex IV), rather than the simple electron guiding hemes B of Complex III. Thus the transmembrane action of Complex I doubles to four (or more) the number of protons and charges translocated per NADH oxidized and Q reduced. The Qny site does not exchange with the pool and may even be covalently bound. (4) The Qnx site on the cytosol side of Complex I is complementary to the Qi site on the matrix side of Complex III and can have the same redox properties. The Qnx site draws QH2 from the membrane pool to be oxidized in two single electron steps. Besides explaining earlier observations and making testable predictions, this Complex I model re-establishes a uniformity in the mechanisms of respiratory energy conversion by using engineering principles common to Complexes III and IV: (1) all the primary energy coupling reactions in the different complexes use oxygen chemistry in the guise of dioxygen or ubiquinone, (2) these reactions are highly localized structurally, utilizing closely placed catalytic redox cofactors, (3) these reactions are also highly localized energetically, since virtually all the free energy defined by substrates is conserved in the form of transition state that initiates the transmembrane action and (4) all complexes possess apparently supernumerary oxidation-reduction cofactors which form classical electron transfer chains that operate with high directional specificity to guide electron at near zero free energies to and from the sites of localized coupling.
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Affiliation(s)
- P L Dutton
- The Johnson Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA.
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10
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Sled VD, Rudnitzky NI, Hatefi Y, Ohnishi T. Thermodynamic analysis of flavin in mitochondrial NADH:ubiquinone oxidoreductase (complex I). Biochemistry 1994; 33:10069-75. [PMID: 8060976 DOI: 10.1021/bi00199a034] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This paper reports the first direct characterization of flavin (noncovalently bound FMN) in energy coupling site I of the mitochondrial respiratory chain. Thermodynamic parameters of its redox reactions were determined potentiometrically monitoring the g = 2.005 signal of its free radical form in isolated bovine heart NADH:ubiquinone oxidoreductase (complex I). The midpoint redox potentials of consecutive one-electron reduction steps are Em1/0 = -414 mV and Em2/1 = -336 mV at pH 7.5. This corresponds to a stability constant of the intermediate flavosemiquinone state of 4.5 x 10(-2). The pK values of the free radical (Fl.-<==>FlH.) and reduced flavin (FlH-<==>FlH2) were estimated as 7.7 and 7.1, respectively. The potentiometrically obtained g = 2.005 flavin free radical EPR signal revealed an unusually broad (2.4 mT) and pH-independent peak-to-peak line width. The spin relaxation of flavosemiquinone in complex I is much faster than that of flavodoxin due to strong dipole-dipole interaction with iron-sulfur cluster N3. Guanidine, an activator of NADH-ferricyanide reductase activity of complex I, was found to have a strong stabilizing effect on the flavin free radical generated both by equilibration with the NADH/NAD+ redox couple and by potentiometric redox titration. The addition of guanidine also leads to a slight modification of the EPR spectrum of iron-sulfur cluster N3. Anaerobic titration of flavosemiquinone free radical with the strictly n = 2 NADH/NAD+ and APADH/APAD+ redox couples revealed that nucleotide binding narrows the EPR signal line width of the flavin free radical to 1.7 mT and changes a shape of the titration curve.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- V D Sled
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia 19104
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11
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van Belzen R, de Jong AM, Albracht SP. On the stoichiometry of the iron-sulphur clusters in mitochondrial NADH: ubiquinone oxidoreductase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 209:1019-22. [PMID: 1330559 DOI: 10.1111/j.1432-1033.1992.tb17377.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The concentration of the iron-sulphur (Fe-S) cluster 1b, present in complex I or soluble high-molecular-mass NADH dehydrogenase, was determined using different methods. It was found that direct double integration of the EPR signal at temperatures higher than 40 K, as is commonly used in this field of research, results in a considerable overestimation of the concentration of cluster 1b. It is demonstrated that this is caused by contributions from the relaxation-broadened signals of the Fe-S clusters 2-4 in the enzyme. The correct way for determining the intensity of the EPR signal of cluster 1b is by comparison with a simulated line shape. It is concluded that the concentration of cluster 1b is half that of cluster 2. This corroborates our proposal based on presteady-state kinetic and inhibitor-titration studies [Van Belzen, R., Van Gaalen, M. C. M., Cuypers, P. A. & Albracht S. P. J. (1990) Biochim. Biophys Acta 1017, 152-159] that the minimal functional unit of mitochondrial NADH:ubiquinone oxidoreductase must be a heterodimer.
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Affiliation(s)
- R van Belzen
- E. C. Slater Institute for Biochemical Research, University of Amsterdam, The Netherlands
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12
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Kotlyar AB, Sled VD, Vinogradov AD. Effect of Ca2+ ions on the slow active/inactive transition of the mitochondrial NADH-ubiquinone reductase. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1098:144-50. [PMID: 1730007 DOI: 10.1016/s0005-2728(05)80329-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Slow active/inactive transition of the membrane-bound mitochondrial NADH-ubiquinone reductase (Kotlyar, A.B. and Vinogradov, A.D. (1990) Biochim. Biophys. Acta 1019, 151-158) is sensitive to Ca2+ and other divalent cations. Millimolar concentrations of Ca2+ drastically reduce the rate of the turnover-dependent activation of NADH-ubiquinone reductase. When NADH oxidase, the rotenone-sensitive NADH-ubiquinone reductase or the succinate-supported delta mu H+-dependent NAD+ reduction were initiated by the deactivated enzyme preparations all the three activities were strongly inhibited by Ca2+; no sensitivity of these reactions to Ca2+ was observed when the assays were started by the activated enzyme preparations. The affinity of the deactivated enzyme to polyvalent cations was in the following order: Ni2+ greater than Co2+ greater than La3+ greater than Mn2+ greater than Ca2+ approximately Mg2+ greater than Ba2+. Monovalent metal cations had no effect on the slow turnover-dependent enzyme activation. The apparent affinity of the deactivated enzyme to Ca2+ was strongly pH-dependent. The KCa2+ values of 5.7 mM and 0.6 mM at pH 7.5 and 8.5 were determined from the presteady-state kinetics parameters. The spontaneous temperature-dependent deactivation of the enzyme was insensitive to Ca2+. Ca2+ increases the reactivity of the enzyme sulfhydryl group in the deactivated preparations towards N-ethylmaleimide. This effect was also used to quantitate Ca2+ affinity for the enzyme. The KCa2+ values of 1.2 mM and 0.4 mM at pH 8.0 and 9.0, respectively, were determined. The data obtained suggest that Ca2+ content in the mitochondrial matrix may play an important role in the control of NADH oxidation by the respiratory chain.
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Affiliation(s)
- A B Kotlyar
- Department of Biochemistry, School of Biology, Moscow State University, U.S.S.R
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13
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Chapter 6 NADH-ubiquinone oxidoreductase. ACTA ACUST UNITED AC 1992. [DOI: 10.1016/s0167-7306(08)60174-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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14
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Kotlyar AB, Sled VD, Burbaev DS, Moroz IA, Vinogradov AD. Coupling site I and the rotenone-sensitive ubisemiquinone in tightly coupled submitochondrial particles. FEBS Lett 1990; 264:17-20. [PMID: 2159893 DOI: 10.1016/0014-5793(90)80753-6] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The rotenone-sensitive g = 2.00 low temperature EPR signal attributed to ubisemiquinone is observed in submitochondrial particles during coupled electron transfer from NADH to oxygen and from succinate to NAD+. The signal is seen only in the presence of oligomycin added to induce the respiratory control (7-9 with NADH and 3-4 with succinate) and it disappears in the presence of uncouplers (CCCP or gramicidin D). No reduction of the iron-sulfur center N-2 in the presence of 20 mM succinate and cyanide is observed, thus suggesting that N-2 is not in equilibrium with the ubiquinone pool. A hypothesis is proposed on delta mu H+ generation coupled with electron transfer between iron-sulfur center N-2 and the ubiquinone pool.
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Affiliation(s)
- A B Kotlyar
- Department of Biochemistry, School of Biology, Moscow State University, USSR
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15
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van Belzen R, Albracht SP. The pathway of electron transfer in NADH:Q oxidoreductase. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 974:311-20. [PMID: 2499359 DOI: 10.1016/s0005-2728(89)80249-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The pre-steady-state reduction by NADPH of NADH:Q oxidoreductase, as present in submitochondrial particles, has been further investigated with the rapid-mixing, rapid-freezing technique. It was found that trypsin treatment, that had previously been used to inactivate the transhydrogenase activity (Bakker, P.T.A. and Albracht, S.P.J. (1986) Biochim. Biophys. Acta 850, 413-422), considerably affected the stability at pH 6.2 of the NAD(P)H oxidation activity of submitochondrial particles. Use of the inhibitor butadione circumvented this problem, thus allowing a more careful investigation of the kinetics at pH 6.2. In the presence of the inhibitor rotenone it was found that 50% of the Fe-S clusters 3 and all of the Fe-S clusters 2 and 4 could be reduced by NADPH within 30 ms at pH 6.2. The remainder of the Fe-S clusters 3 and all of the Fe-S clusters 1 were reduced slowly (complete reduction only after more than 60 s). It was concluded that these latter Fe-S clusters play no role in the NADPH oxidation activity. In the absence of rotenone at pH 6.2 only 50% of the Fe-S clusters 2-4 could be reduced within 30 ms, while Fe-S cluster 1 was again not reduced. This difference was attributed to the fast reoxidation of part of the Fe-S clusters 2 and 4 by ubiquinone. At pH 8.0, where the NADPH oxidation activity is almost zero, 50% of the Fe-S clusters 2-4 could still be reduced by NADPH within 30 ms, while Fe-S cluster 1 was not reduced. The presence of rotenone had no effect on this reduction. From these observations it is concluded that the Fe-S clusters 2 and 4, which were rapidly reduced by NADPH and reoxidised by ubiquinone at pH 6.2, could not be reduced by NADPH at 8.0. This provides an explanation why NADH:Q oxidoreductase was not able to oxidise NADPH at pH 8.0, while part of the Fe-S clusters were still rapidly reduced. As a working hypothesis a dimeric structure for NADH:Q oxidoreductase is proposed. One protomer (B) contains FMN and Fe-S clusters 1-4 in equal amounts; the other protomer (A) is identical except for the absence of Fe-S cluster 1. NADH is able to react with both protomers, while NADPH only reacts with protomer A. A pH-dependent electron transfer from protomer A to protomer B is proposed, which would allow the reduction of Fe-S clusters 2 and 4 of protomer B by NADPH at pH 6.2, which is required for NADPH:Q oxidoreductase activity.
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Affiliation(s)
- R van Belzen
- University of Amsterdam, Amsterdam, The Netherlands
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16
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Tanaka K, Masanaga M, Tanaka T. Electron Coupled Proton Transport Mediated by [Fe 4S 4(SC 6H 4- p- n-C 8H 17) 4] 2−in Liquid Membrane. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1988. [DOI: 10.1246/bcsj.61.1285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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17
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Bakker PT, Albracht SP. Evidence for two independent pathways of electron transfer in mitochondrial NADH:Q oxidoreductase. I. Pre-steady-state kinetics with NADPH. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 850:413-22. [PMID: 3015206 DOI: 10.1016/0005-2728(86)90109-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The reduction of NADH:Q oxidoreductase by NADPH occurring in submitochondrial particles has been studied with the freeze-quench technique. It was found that 50% of the Fe-S clusters 2, 3 and 4 could be reduced by NADPH within 30 ms at pH 6.5. The remainder of the clusters, including cluster 1, were reduced slowly and incompletely; it was concluded that these clusters play no role in the NADPH oxidase activity. Nearly the same results were obtained at pH 8 under anaerobic conditions, demonstrating that the rate of reaction of NADPH with the enzyme was essentially the same at both pH values. The rate and extent of reduction of half of the clusters 2 by NADPH at pH 8 were not affected by the presence of O2 of rotenone. This implies a pH-dependent oxidation of the enzyme as the cause for the absence of the NADPH oxidase activity at this pH. A dimeric model of the enzyme is proposed in which one protomer, containing FMN and the Fe-S clusters 1-4 in stoichiometric amounts, is responsible for NADH oxidation at pH 8. This protomer cannot react with NADPH. The other protomer, containing only FMN and the clusters 2, 3 and 4, is supposed to catalyse the oxidation of NADPH. The oxidation of this protomer by ubiquinone is expected to be strongly dependent on pH. This protomer might also catalyse NADH oxidation at pH 6-6.5.
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Spectroscopic characterization of the number and type of iron-sulfur clusters in NADH:ubiquinone oxidoreductase. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)67645-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Kuila D, Fee JA. Evidence for a redox-linked ionizable group associated with the [2Fe-2S] cluster of Thermus Rieske protein. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(17)35851-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Beinert H, Albracht SP. New insights, ideas and unanswered questions concerning iron-sulfur clusters in mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 683:245-77. [PMID: 6297553 DOI: 10.1016/0304-4173(82)90003-9] [Citation(s) in RCA: 143] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Origin of the pH dependence of the midpoint reduction potential in Clostridium pasteurianum ferredoxin:oxidation state-dependent hydrogen ion association. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34807-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Ohnishi T, Blum H, Galante YM, Hatefi Y. Iron-sulfur N-1 clusters studied in NADH-ubiquinone oxidoreductase and in soluble NADH dehydrogenase. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)52531-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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26
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The Electron Transport System and Hydrogenase of Paracoccus denitrificans. CURRENT TOPICS IN BIOENERGETICS 1981. [DOI: 10.1016/b978-0-12-152512-5.50009-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Ingledew WJ, Ohnishi T. An analysis of some thermodynamic properties of iron-sulphur centres in site I of mitochondria. Biochem J 1980; 186:111-7. [PMID: 6245637 PMCID: PMC1161509 DOI: 10.1042/bj1860111] [Citation(s) in RCA: 137] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
1. The midpoint potentials of the various iron-sulphur centres in Site I were determined at different pH values by the technique of redox potentiometry. An interesting feature is the pH-dependence of Centre N-2, the highest potential component of the NADH dehydrogenase segment of the respiratory chain. 2. The apparent midpoint potentials of Centre N-2 (NADH dehydrogenase) and S-1 (succinate dehydrogenase) and their pH-dependence was also determined by using the succinate/fumarate couple. Again Centre N-2 is pH-dependent in midpoint potential, and Centre S-1 is not. The results obtained by titrating with the succinate/fumarate couple are in quantitative agreement with those obtained for these centres by redox potentiometry. 3. Oxidation-reduction titrations of iron-sulphur centres with the couple NADH/NAD+ and an analogue APADH/APAD+ in the presence of rotenone gave results substantially different from those obtained by redox potentiometry; these differences may be due to the mechanism of action of NADH dehydrogenase and its specific interaction with NADH. 5. The addition of ATP to an NAD+/NADH-poised system induces an uncoupler-sensitive oxidation of Centre N-4.
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Respiration-Linked H+ Translocation in Mitochondria: Stoichiometry and Mechanism. CURRENT TOPICS IN BIOENERGETICS 1980. [DOI: 10.1016/b978-0-12-152510-1.50009-2] [Citation(s) in RCA: 106] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Rupp H, Moore AL. Characterization of iron-sulphur centres of plant mitochondria by microwave power saturation. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 548:16-29. [PMID: 226132 DOI: 10.1016/0005-2728(79)90183-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The electron spin relaxation of iron-sulphur centres and ubisemiquinones of plant mitochondria was studied by microwave power saturation of the respective EPR signals. In the microwave power saturation technique, the experimental saturation data were fitted by a least-squares procedure to a saturation function which is characterized by the power for half-saturation (P1/2) and the inhomogeneity parameter (b). Since the theoretical saturation curves were based on a one-electron spin system, it became possible to differentiate between EPR signals of iron-sulphur centres which have similar g values but different P1/2 values. If the difference in the P1/2 values of the overlapped components was small, no significant deviation from these theoretical saturation curves was observed, as shown for the overlapped signals of centre S-3 and the Ruzicka centre of mung bean mitochondria. By contrast, the microwave power saturation data for the g = 1.93 signal (17--26 K) of Arum maculatum submitochondrial particles reduced by succinate could not be fitted using one-electron saturation curves. Reduction by NADH resulted in a stronger deviation. Since the iron-sulphur centres of Complex I were present only in an unusually low concentration in A. maculatum mitochondria, it was proposed that an iron-sulphur centre of the external NADH dehydrogenase contributes to the spectrum of centre S-1. For mung bean mitochondria, the g = 1.93 signal below 20 K could be attributed mainly to centre N-2. The microwave power saturation technique was also suitable for detecting magnetic interactions between paramagnetic centres. From the saturation data of the complex spectrum attributable to centre S-3 and an interacting ubisemiquinone pair in mung bean mitochondria (oxidized state) followed that centre S-3 has a faster electron spin relaxation than the ubisemiquinone molecules. It is noteworthy that the differences in the relaxation rates were maintained despite the interaction between centre S-3 and the ubisemiquinones. Furthermore, a relaxation enhancement was observed for centre S-1 of A. maculatum submitochondrial particles upon reduction of centre S-2 by dithionite. This indicated a magnetic interaction between centres S-1 and S-2.
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Walz D. Thermodynamics of oxidation-reduction reactions and its application to bioenergetics. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 505:279-353. [PMID: 219888 DOI: 10.1016/0304-4173(79)90007-7] [Citation(s) in RCA: 110] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Meijer EM, Schuitenmaker MG, Boogerd FC, Wever R, Stouthamer AH. Effects induced by rotenone during aerobic growth of Paracoccus denitrificans in continuous culture. Changes in energy conservation and electron transport associated with NADH dehydrogenase. Arch Microbiol 1978; 119:119-27. [PMID: 727852 DOI: 10.1007/bf00964262] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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33
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Commack R, Maguire JJ, Packer L. Interaction of ionic detergents with iron-sulfur centers in beef heart mitochondrial membranes. FEBS Lett 1978; 93:278-82. [PMID: 213312 DOI: 10.1016/0014-5793(78)81121-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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34
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Aggarwal BB, Quintanilha AT, Cammack R, Packer L. Damage to mitochondrial electron transport and energy coupling by visible light. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 502:367-82. [PMID: 656406 DOI: 10.1016/0005-2728(78)90057-9] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The effect of treating mitochondria with visible light above 400 nm on electron transport and coupled reactions was examined. The temporal sequence of changes was: stimulation of respiration coupled to ATP synthesis, a decline in ATP synthesis, inactivation of respiration, increased ATPase activity and, later, loss of the membrane potential. Loss of respiration was principally due to inactivation of dehydrogenases. Of the components of dehydrogenase systems, flavins and quinones were most susceptible to illumination, the iron-sulfur centers were remarkably resistant to being damaged. Succinate dehydrogenase was inactivated before choline and NADH dehydrogenase. Redox reactions of cytochromes and cytochrome c oxidase activity were unaffected. Inactivation was O2-dependent and prevented by anaerobiosis or the presence of substrates for the dehydrogenases. Light in the range 400-500 nm was most effective and the presence of free flavins greatly enhanced inactivation of all of the above mitochondrial activities. This suggests that visible light mediates a flavin-photosensitized reaction that initiates damage involving participation of an activated species of oxygen in the damage propagation.
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Meijer EM, Wever R, Stouthamer AH. The role of iron-sulfur center 2 in electron transport and energy conservation in the NADH-ubiquinone segment of the respiratory chain in Paracoccus denitrificans. EUROPEAN JOURNAL OF BIOCHEMISTRY 1977; 81:267-75. [PMID: 202453 DOI: 10.1111/j.1432-1033.1977.tb11948.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
1. The electron paramagnetic resonance spectra at 15 K of reduced membrane particles of Paracoccus denitrificans exhibit resonance signals with g values, line shapes and temperature profile which are similar to the signals of the iron-sulfur centers observed in the NADH-ubiquinone segment of mitochondrial respiratory chains. These iron-sulfur centers are reducible with NADH, NADPH as well as chemically with dithionite. 2. Sulphate-limited growth of Paracoccus denitrificans results in the loss of an electron paramagnetic resonance signal (gz approximately 2.05, gy approximately gx approximately 1.92) which has properties similar to those of iron-sulfur center 2 of the NADH dehydrogenase of mitochondrial origin. The loss of this signal is accompanied by a decrease in the NADH oxidase and NADH ferricyanide oxidoreductase activities to respectively 30 and 40% of the values found for succinate-limited growth conditions. In addition respiration in membrane particles from sulphate-limited cells loses its sensitivity to rotenone. 3. Since sulphate-limited growth of Paracoccus denitrificans induces loss of site I phosphorylation [Arch. Microbiol. (1977) 112, 25-34] these observations suggest a close correlation between site I phosphorylation, rotenone-sensitivity and the presence of an electron paramagnetic resonance signal with gz approximately 2.05 and gy approximately gx approximately 1.92.
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Cammack R, Palmer JM. Iron-sulphur centres in mitochondria from Arum maculatum spadix with very high rates of cyanide-resistant respiration. Biochem J 1977; 166:347-55. [PMID: 597230 PMCID: PMC1165016 DOI: 10.1042/bj1660347] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
X-band electron-paramagnetic-resonance spectroscopy at 4.2--77K combined with measurements of oxidation-reduction potential was used to identify iron--sulphur centres in Arum maculatum (cuckoo-pint) mitochondria. In the oxidized state a signal with a derivative maximum at g = 2.02 was assigned to succinate dehydrogenase centre S-3. Unreduced particles showed additional signals at g = 2.04 and 1.98 (at 9.2 GHz), which may be due to a spin-spin interaction. In the reduced state a prominent signal at g = 1.93 and 2.02 was resolved into at least three components that could be assigned to centres S-1 and S-2 of succinate dehydrogenase (midpoint potentials -7 and -240 mV respectively at pH 7.2) and a small amount of centre N-1b (e'o= -240 mV) of NADH-ubiquinone reductase. In addition, changes in line shape around -10 mV indicated the presence of a fourth component in this signal. The latter was more readily reduced by NADH than by succinate, suggesting that it might be associated with the external NADH dehydrogenase. The iron-sulphur centres of NADH-ubiquinone reductase were present in an unusually low concentration, indicating that the alternative, non-phosphorylating, NADH dehydrogenase containing a low number of iron-sulphur centres may be responsible for most of the high rate of oxidation of NADH.
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Rottenberg H, Gutman M. Control of the rate of reverse electron transport in submitochondrial particles by the free energy. Biochemistry 1977; 16:3220-7. [PMID: 196630 DOI: 10.1021/bi00633a028] [Citation(s) in RCA: 87] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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38
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How Oxygen Meets the Electrons with Generation of ATP, and Other Stories. Biochemistry 1977. [DOI: 10.1016/b978-0-12-492550-2.50015-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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