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Showing 1 to 14 of 14 for “"quinone binding"”.
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Structural and Functional Studies on Cytochrome BO3 Ubiquinol Oxidase From Escherichia Coli and the Characterization of Its Quinone Binding Sites
… mechanism. A tightly but non-covalently bound ubiquinone is retained in the purified enzyme at the high affinity quinone binding (QH) site, and is able to transiently form a one-electron reduced semiquinone radical during the catalytic cycle. The semiquinone is highly stabilized at the QH site, …
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Biochemical characterization of a-type heme-copper oxidases in escherichia coli, bacillus subtilis and thermus thermophilus
… (Arg71, Asp75, His98, and Gln101) involved in ubiquinone semiquinone radical stabilization at quinone binding site in E. coli cytochrome bo3 oxidase. Similar result was reported on cytochrome aa3-600 oxidase in B. subtilis, a close homolog to cytochrome bo3 that uses menaquinone instead of …
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Structural and functional studies of mitochondrial NADH:ubiquinone oxidoreductase (complex I)
NADH:ubiquinone oxidoreductase (complex I) is the largest and most complicated enzyme in the mitochondrial electron transfer chain. It catalyses the oxidation of NADH and the reduction of ubiquinone, coupled to the translocation of protons across the mitochondrial inner membrane, maintaining the …
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Studies on assembly and genetic variation in mitochondrial respiratory complex I
Complex I (NADH:ubiquinone oxidoreductase) couples electron transfer to proton translocation across the inner mitochondrial membrane, to drive the synthesis of ATP. Its distinctive L-shaped structure comprises 45 subunits, encoded by both the mitochondrial and nuclear genomes, which are assembled …
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The interactions of cytochrome bo3 from Escherichia coli with its substrates - ubiquinone and oxygen
… enzyme contain between 0 to 2 equivalents of ubiquinone-8. Studies using ubiquinol-1, a soluble quinol substrate, indicate one high affinity quinone binding site, which acts as a non-exchanging co-factor, and a second, low-affinity site which is the substrate site. The residues interacting with …
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Computer-Aided Drug Discovery for Helicobacter pylori
… found H. pylori complex I inhibitor, and known quinone binding. The docking grid was validated using a library of known actives and DUD-E generated decoys through enrichment. The validated model provided an AU-ROC of 0.92 and was used to determine a threshold for selecting molecules for …
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Computer simulation of titration behavior in proteins
… in which two critical residues in the secondary quinone binding site of the reaction center are altered are shown to be proton uptake impaired, with respect to the wild type.
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Interfacial modulation of protein function explored through atomistic molecular dynamics simulation
… bilayers. Separately, simulations of C2 domain binding of synaptogamin (Syt) to the HMMM demonstrate clear differences in the binding properties between Syt isoforms, and explain the atomic origins of the observed differential kinetics between Syt-1 and Syt-7. Development of the HMMM to extend …
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Inhibitor-Quinone Interactions in Reaction Centers From Rhodopseudomonas Sphaeroides (Herbicide, Triazine, Ubiquinone, Photosynthesis, Resistance)
The properties of ubiquinone and inhibitor binding to reaction centers (RCs) from the photosynthetic bacterium Rhodopseudomonas sphaeroides were studied. The charge recombination pathway between the primary electron donor, P, and the primary ubiquinone electron acceptor, Q(,A), or the secondary …
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The Binding Pockets of QA and QB in the Photosynthetic Reaction Center of Rba. sphaeroides Probed by Pulsed EPR
… of cofactors, the final two are identical ubiquinones (QA and QB). Both ubiquinones can be stabilized in their reduced (semiquinone) state allowing for their binding pockets to be studied with EPR (electron paramagnetic resonance) spectroscopy. Using the pulsed EPR technique, ESEEM (electron …
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The Mechanism of Bicarbonate Activation of Plastoquinone Reduction in Photosystem II of Photosynthesis
… slows down electron transfer from the primary quinone acceptor Q$\sb{\rm A}$ to the secondary quinone acceptor Q$\sb{\rm B}$. It also blocks electron transfer from Q$\sb{\rm B}$ to the plastoquinone (PQ) pool. This effect is reversible, and is specific for HCO$\sb{3}\sp{-}$. A variety of …
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Studies on the structure, function and mechanisms of the cbb3 type cytochrome c oxidase from Vibrio cholerae and the cytochrome bo3 ubiquinol oxidase from Escherichia coli
… by quinol analogues. To facilitate the study of quinone binding sites of bo3, a competitive inhibitor aurachin 1-10 was synthesized through a seven-step synthetic route as my preliminary work on bo3 project. When mixed-valence cytochrome c oxidase (R2) reacts with dioxygen, the first adduct …
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Structure and function studies of polar mutants of the QA pocket in the bacterial photosynthetic reaction center of Rhodobacter sphaeroides
… the final two electron acceptors, the primary quinone (QA) that then reduce the secondary quinone (QB). In Rb. sphaeroides these quinones are chemically identical ubiquinones and the protein must tune the midpoint potential (Em) of each quinone to make electron transfer from QA to QB favorable. …
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EPR and solid-state NMR studies on the mechanism of cytochrome bo3 ubiquinol oxidase from escherichia coli
… the ubiquinol pool are first transferred to a ubiquinone cofactor bound at the high affinity binding site known as the QH-site, from which electrons are moved one at a time sequentially to the low-spin heme b and the CuB-heme o3 catalytic site. In this study, E. coli C43(DE3) auxotroph strains …