Iron Centers
Mostrando 25-36 de 109 artigos, teses e dissertações.
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25. Appearance of Membrane-bound Iron-Sulfur Centers and the Photosystem I Reaction Center during Greening of Barley Leaves 1
Dark-grown barley (Hordeum vulgare) etioplasts were examined for their content of membrane-bound iron-sulfur centers by electron paramagnetic resonance spectroscopy at 15K. They were found to contain the high potential iron-sulfur center characterized (in the reduced state) by an electron paramagnetic resonance g value of 1.89 (the “Rieske” center) but d
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26. Characterization of the iron-sulfur centers in succinate dehydrogenase.
Two techniques have been applied to the determination of the number and type (2-Fe, 4-Fe) of iron-sulfur centers in the iron-sulfur flavoprotein succinate dehydrogenase [succinate:(acceptor) oxidoreductase, EC 1.3.99.1]. One procedure uses p-CF3C6H4SH as an extrusion reagent and Fourier transform 19F nuclear magentic resonance as the method of detection and
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27. Iron-oxo clusters biomineralizing on protein surfaces: Structural analysis of Halobacterium salinarum DpsA in its low- and high-iron states
The crystal structure of the Dps-like (Dps, DNA-protecting protein during starvation) ferritin protein DpsA from the halophile Halobacterium salinarum was determined with low endogenous iron content at 1.6-Å resolution. The mechanism of iron uptake and storage was analyzed in this noncanonical ferritin by three high-resolution structures at successively inc
National Academy of Sciences.
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28. Oxidation of microbial iron-sulfur centers by the myeloperoxidase-H2O2-halide antimicrobial system.
Myeloperoxidase, H2O2, and a halide (chloride, bromide, or iodide) form a potent microbicidal system that contributes to the antimicrobial activity of neutrophils. The mechanism of toxicity is not completely understood. Powerful oxidants are formed that presumably attack the microbe at a variety of sites. Among the consequences of this attack is the release
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29. Shared thematic elements in photochemical reaction centers.
The structural, functional, and evolutionary relationships between photosystem II and the purple nonsulfur bacterial reaction center have been recognized for several years. These can be classified as "quinone type" (type II) photosystems because the terminal electron acceptor is a mobile quinone molecule. The analogous relationship between photosystem I and
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30. Electron paramagnetic resonance studies of photosynthetic electron transport: Photoreduction of ferredoxin and membrane-bound iron-sulfur centers*
Electron paramagnetic resonance spectrometry was used to investigate, at physiological temperatures, light-induced electron transport from membrane-bound iron-sulfur components (bound ferredoxin) to soluble ferredoxin and NADP+ in membrane fragments (from the blue-green alga, Nostoc muscorum) that had high rates of electron transport from water to NADP+ and
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31. Identification of iron-sulfur centers in the iron-molybdenum proteins of nitrogenase.
The core extrusion method has been applied to the determination of the type ([2Fe-2S], [4Fe-4S]) and number of iron-sulfur centers in the FeMo proteins of the nitrogenases from Clostridium pasteurianum and Azotobacter vinelandii. The method involves extrusion with o-xylyl-alpha, alpha'-dithiol, ligand exchange of the extrusion products with p-CF3C6H4SH (RFSH
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32. Effects of Iron Limitation on Photosystem II Composition and Light Utilization in Dunaliella tertiolecta.
The effects of iron limitation on photosystem II (PSII) composition and photochemical energy conversion efficiency were studied in the unicellular chlorophyte alga Dunaliella tertiolecta. The quantum yield of photochemistry in PSII, inferred from changes in variable fluorescence normalized to the maximum fluorescence yield, was markedly lower in iron-limited
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33. Formate dehydrogenase of Clostridium pasteurianum.
Formate dehydrogenase was purified to electrophoretic homogeneity from N2-fixing cells of Clostridium pasteurianum W5. The purified enzyme has a minimal Mr of 117,000 with two nonidentical subunits with molecular weights of 76,000 and 34,000, respectively. It contains 2 mol of molybdenum, 24 mol of nonheme iron, and 28 mol of acid-labile sulfide per mol of e
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34. Resolution of component proteins in an enzyme complex from Methanosarcina thermophila catalyzing the synthesis or cleavage of acetyl-CoA.
An enzyme complex was isolated from acetate-grown Methanosarcina thermophila that oxidized CO and catalyzed the synthesis or cleavage of acetyl-CoA. The complex consisted of five subunits (alpha1beta1gamma1delta1epsilon1) of 89, 71, 60, 58, and 19 kDa. The complex contained nickel, iron, acid-labile sulfide, and cobalt in a corrinoid cofactor. Two components
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35. Isolation and characterization of an Fe,-S8 ferredoxin (ferredoxin II) from Clostridium thermoaceticum.
A second ferredoxin protein was isolated from the thermophilic anaerobic bacterium Clostridium thermoaceticum and termed ferredoxin II. This ferredoxin was found to contain 7.9 +/- 0.3 iron atoms and 7.4 +/- 0.4 acid-labile sulfur atoms per mol of protein. Extrusion studies of the iron-sulfur centers showed the presence of two [Fe4-S4] centers per mol of pro
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36. Cloning and Molecular Characterization of the Genes for Carbon Monoxide Dehydrogenase and Localization of Molybdopterin, Flavin Adenine Dinucleotide, and Iron-Sulfur Centers in the Enzyme of Hydrogenophaga pseudoflava
Carbon monoxide dehydrogenases (CO-DH) are the enzymes responsible for the oxidation of CO to carbon dioxide in carboxydobacteria and consist of three nonidentical subunits containing molybdopterin flavin adenine dinucleotide (FAD), and two different iron-sulfur clusters (O. Meyer, K. Frunzke, D. Gadkari, S. Jacobitz, I. Hugendieck, and M. Kraut, FEMS Microb
American Society for Microbiology.