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Showing 1 to 20 of 69 for “"Nitrogenase"”.
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Study of Nitrogenase Cofactors bound to Nitrogenase Carrier Proteins
Nitrogenases employ Fe-S clusters as catalytic cofactors to perform the kinetically challenging reduction of N₂ to NH₃. The unique reactivity of nitrogenase cofactors is derived in part from the complexity of their cluster composition, featuring eight metal sites, at least seven of which are Fe. …
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Spectroscopic and mechanistic studies of nitrogenase
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1996.
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The Biosynthesis and Function of Nitrogenase Metalloclusters
Nitrogenase catalyzes the biological reduction of N2 to ammonia (nitrogen fixation). The metalloclusters associated with the nitrogenase components include the [4Fe-4S] cluster of the Fe protein, and the P-cluster [8Fe7S] and FeMo-cofactor [7Fe-9S-Mo-X-homocitrate], both contained within the MoFe …
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Preparation of isotopically labeled MoFe protein of nitrogenase
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1996.
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Site-selective Labeling of the Nitrogenase Iron-Molybdenum Cofactor
Nitrogenases are enzymes known to catalyze the kinetically challenging, and biologically important, reduction of N₂ to NH₃. The mechanism of these enzymes, and in particular, the chemistry that occurs at the catalytic cofactor of the Mo nitrogenase, the iron- molybdenum cofactor (FeMo-co), has been …
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The pathway of electron transfer within the nitrogenase complex
… to probe the pathway of electron transfer in nitrogenase by substituting single or groups of amino acid residues that, within the current view of component protein docking and nitrogenase catalysis, are likely to be involved in inter- or intra-molecular electron transfer. Intermolecular …
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Evaluation of Nitrogenase Genes as Markers in Soil Microbial Community Studies
Molecular tools were developed to overcome some of the constraints to analyzing nitrogen-fixing bacteria in the environment. Two distinct plant-microbe systems were used to develop these tools, and to evaluate their utility and flexibility. The first system focused on nitrogen-fixing bacteria in …
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Development of a Model for the Kinetics and Mechanism of Nitrogenase
<p>Nitrogenase has a central role in the global nitrogen cycle as the enzyme that catalyzes the reduction of atmospheric N2 to NH3. Fixed nitrogen is generally limiting in the environment and in agriculture, so nitrogenase has received much attention as an alternative to nitrogen fertilizers. …
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Site-directed mutagenesis of the nitrogenase MoFe protein from Azotobacter vinelandii
… (P-clusters) within the Azotobacter vinelandii nitrogenase MoFe protein is presented. Based on interspecies and intersubunit amino acid comparisons of the α- and ß-subunits of the MoFe protein, and the FeMoco biosynthetic proteins, NifE and NifN, four conserved residues (Cys62, His83, Cys88, …
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Studies of the cloning and expression of Thiobacillus Ferrooxidans Plasmid and Nitrogenase genes
… and in vitro systems of the T. ferrooxidans nitrogenase structural genes were studied.
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Feedback regulation of nitrogenase and response of a hypernodulating soybean mutant to increased photosynthate supply
The hypothesis that nitrogenase activity may be related to N and C levels in plant tissues was evaluated. Soybean (Glycine max L. Merr.) plants were grown in growth chambers using a hydroponic system. A wide range of C:N ratios in various plant tissues was generated through a combination of light, …
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Azotobacter vinelandii nitrogenase: role of the MoFe protein α-subunit histidine-195 residue in catalysis
… the role of the α-histidine-195 residue in nitrogenase catalysis by examining the altered MoFe proteins. Comparisons of the catalytic and spectroscopic properties of altered MoFe proteins produced by the <i>Azotobacter vinelandii</i> mutant strains suggest that the α-histidine-195 residue …
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Spectroscopic investigation of nitrogenase: EPR and MCD studies of the FeMo cofactor and the P-cluster
… known about substrate binding and reduction of nitrogenase. EPR spectroscopy is used here to observe intermediate states generated by different substrates. Two different spin states (S=3/2 and S=1/2) were exhibited for each substrate, which may result from different binding of the substrate to …
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Azotobacter vinelandii Nitrogenase: Multiple Substrate-Reduction Sites and Effects of pH on Substrate Reduction and CO Inhibition
Mo-nitrogenase consists of two component proteins, the Fe protein and the MoFe protein. The site of substrate binding and reduction within the Mo-nitrogenase is provided by a metallocluster, the FeMo cofactor, located in the a-subunit of the MoFe protein. The FeMo cofactor's polypeptide environment …
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Role of the MoFe Protein β-95-Cysteinyl Residue in Nitrogenase Catalysis in <i>Azotobacter vinelandii</i>
… on the P cluster within the MoFe protein of nitrogenase, and a limited number of substitutions at this position resulted in inactive nitrogenase. It was also found that the counterpart of β-95-Cys, α-88-Cys, which also acts as a cysteinyl ligand to the P cluster, is replaceable without a …
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Coordination of Carbon Dioxide and Nitrogen Metabolism in Rhodobacter sphaeroides
… is capable of nitrogen fixation via nitrogenase catalysis and carbon dioxide fixation via the Calvin-Benson-Bassham (CBB) cycle. When the CBB cycle was inactivated through gene deletions, strains developed that deregulated nitrogenase. Genomic sequencing and comparative analyses of …
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