A Novel, Enzymatically Active Conformation of the Escherichia coli NADH:Ubiquinone Oxidoreductase (Complex I)

Böttcher, Bettina; Scheide, Dierk; Hesterberg, Micaela; Nagel-Steger, Luitgard; Friedrich, Thorsten

doi:10.1074/jbc.m112357200

Cited by 94 publications

(85 citation statements)

References 41 publications

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“…Our results show that the catalytic cycle of complex I is not likely to involve large movements of the peripheral arm relative to the membrane arm, as discussed elsewhere (12,37). The conformational change shown in Fig.…”

Section: Discussionsupporting

confidence: 50%

“…One arm is embedded in the membrane and the other, the peripheral arm, protrudes into the mitochondrial matrix or bacterial cytoplasm (6 -11). An alternative conformation of complex I from Escherichia coli has been proposed recently (12), but the existence of this conformation was not confirmed in our laboratory (13). The membrane and peripheral arms contain mainly hydrophobic and hydrophilic subunits, respectively.…”

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confidence: 86%

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Substrate-induced Conformational Change in Bacterial Complex I

Mamedova

Holt

Carroll

et al. 2004

Journal of Biological Chemistry

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The mechanism coupling electron transfer and proton pumping in respiratory complex I (NADH-ubiquinone oxidoreductase) has not been established, but it has been suggested that it involves conformational changes. Here, the influence of substrates on the conformation of purified complex I from Escherichia coli was studied by cross-linking and electron microscopy. When a zerolength cross-linking reagent was used, the presence of NAD(P)H, in contrast to that of NAD ؉ , prevented the formation of cross-links between the hydrophilic subunits of the complex, including NuoB, NuoI, and NuoCD. Comparisons using different cross-linkers suggested that NuoB, which is likely to coordinate the key ironsulfur cluster N2, is the most mobile subunit. The presence of NAD(P)H led also to enhanced proteolysis of subunit NuoG. These data indicate that upon NAD(P)H binding, the peripheral arm of the complex adopts a more open conformation, with increased distances between subunits. Single particle analysis showed the nature of this conformational change. The enzyme retains its L-shape in the presence of NADH, but exhibits a significantly more open or expanded structure both in the peripheral arm and, unexpectedly, in the membrane domain also.

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Section: Discussionsupporting

confidence: 50%

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confidence: 86%

Substrate-induced Conformational Change in Bacterial Complex I

Mamedova

Holt

Carroll

et al. 2004

Journal of Biological Chemistry

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“…Low resolution electron microscopy analyses [3][4][5][6][7][8][9][10] show that complex I is structurally organized in two major domains: a membrane spanning segment and a peripheral arm, which protrudes into the mitochondrial matrix (or the bacterial cytosol). Sazanov and Hinchliffe reported the crystal structure of the hydrophilic domain of complex I from the bacterium Thermus (T) thermophilus at 3.3 Å resolution [11].…”

Section: Introductionmentioning

confidence: 99%

EXAFS reveals a structural zinc binding site in the bovine NADH‐Q oxidoreductase

et al. 2007

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The metal content of bovine NADH-Q oxidoreductase determined by inductively-coupled plasma atomic-emission spectroscopy reveals the presence of about one atom of zinc per molecule of flavin mononucleotide. We applied Zn K-edge extended X-ray absorption fine structure spectroscopy (EXAFS) to investigate the local structure of the bound zinc ion and to identify the nature of the coordinating residues. The EXAFS spectrum is consistent with a structured zinc binding site. By combining information from first-shell analysis and from metalloprotein data bases putative binding clusters have been built and fitted to the experimental spectrum using ab initio simulations. The best fitting binding cluster is formed by two histidine and two cysteine residues arranged in a tetrahedral geometry.

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“…Complex I catalyzes the transfer of electrons from matrix NADH to membrane ubiquinone coupled to the translocation of four protons across the membrane (10,11). Numerous hypothetical schemes for the coupling mechanism of complex I can be found in the literature; the most recent ones involve long range conformational changes in the enzyme complex rather than variations of a classical redox loop or pump (12)(13)(14)(15). In the presence of ⌬H ϩ across the membrane, the enzyme is also able to catalyze the reverse reaction and reduce NAD ϩ by the quinol pool (16,17).…”

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Superoxide Radical Formation by Pure Complex I (NADH:Ubiquinone Oxidoreductase) from Yarrowia lipolytica

Galkin¹,

Brandt

2005

Journal of Biological Chemistry

152

110

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Generation of reactive oxygen species (ROS) is increasingly recognized as an important cellular process involved in numerous physiological and pathophysiological processes. Complex I (NADH:ubiquinone oxidoreductase) is considered as one of the major sources of ROS within mitochondria. Yet, the exact site and mechanism of superoxide production by this large membrane-bound multiprotein complex has remained controversial. Here we show that isolated complex I from Yarrowia lipolytica forms superoxide at a rate of 0.15% of the rate measured for catalytic turnover. Superoxide production is not inhibited by ubiquinone analogous inhibitors. Because mutant complex I lacking a detectable iron-sulfur cluster N2 exhibited the same rate of ROS production, this terminal redox center could be excluded as a source of electrons. From the effect of different ubiquinone derivatives and pH on this side reaction of complex I we concluded that oxygen accepts electrons from FMNH 2 or FMN semiquinone either directly or via more hydrophilic ubiquinone derivatives.Over the last decade the processes leading to the production of superoxide and other reactive oxygen species (ROS) 1 have gained much attention. ROS seem to be involved in apoptosis, the development of various pathological states, aging, and the regulation of cell metabolism. It is generally accepted that production of reactive oxygen species is an inherent property of the mitochondrial respiratory chain of eucaryotic cells. Oxidation of certain redox centers in complex I and III by molecular oxygen results in the production of superoxide anion radical O 2. (see Ref. 1 for a review). Superoxide can then convert into hydrogen peroxide, the highly active hydroxyl radical (OH ⅐ ), and other ROS. It has been shown that O 2 . production by complex I occurs in the mitochondrial matrix, whereas the cytochrome bc 1 complex reduces oxygen primarily on the intermembrane side (2, 3) (see, however, Ref. 4). It has been demonstrated for the cytochrome bc 1 complex that oxygen reduction occurs at the Q P site and is increased markedly under conditions of "oxidant-induced reduction" (5, 6). However, much less is known about the site and mechanism of O 2 . generation in complex I. Thermodynamically, any of the complex I redox centers in the reduced state is capable of donating an electron to molecular oxygen to form a superoxide anion. Eucaryotic NADH:ubiquinone oxidoreductase (complex I or type I NADH dehydrogenase) is the largest and most complex enzyme of the respiratory chain, residing in the inner membrane of mitochondria. In mammals, the enzyme is composed of 46 different subunits (7) and contains non-covalently bound FMN and up to eight iron-sulfur clusters as redox cofactors. Two complex I-associated, electron paramagnetic resonancedetectable semiquinone species with different spin relaxation times have been characterized (8, 9). Complex I catalyzes the transfer of electrons from matrix NADH to membrane ubiquinone coupled to the translocation of four protons across the membrane (10, 11...

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A Novel, Enzymatically Active Conformation of the Escherichia coli NADH:Ubiquinone Oxidoreductase (Complex I)

Cited by 94 publications

References 41 publications

Substrate-induced Conformational Change in Bacterial Complex I

Substrate-induced Conformational Change in Bacterial Complex I

EXAFS reveals a structural zinc binding site in the bovine NADH‐Q oxidoreductase

Superoxide Radical Formation by Pure Complex I (NADH:Ubiquinone Oxidoreductase) from Yarrowia lipolytica

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