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Showing 1 to 17 of 17 for “"MoFe protein"”.
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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-directed mutagenesis of the nitrogenase MoFe protein from Azotobacter vinelandii
… 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, Cys154 all …
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Characterization of an altered MoFe protein from a nifV- strain from Azotobacter vinelandii
… within the a-subunit of the molybdenum iron protein. FeMo co consists of a metal sulfur core composed of an FeS cluster bridged by three inorganic sulfides to a MoFeS cluster. An organic acid, homocitrate, is coordinated to the Mo atom through its 2-carboxy and 2-hydroxy groups. Homocitrate …
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Azotobacter vinelandii nitrogenase: role of the MoFe protein α-subunit histidine-195 residue in catalysis
… vinelandii</i> that produce altered MoFe proteins where the α-subunit residue-195 position, normally occupied by a histidine residue, was individually substituted by a variety of other amino acids. Structural studies have revealed that this histidine residue is associated with the …
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Role of the MoFe Protein β-95-Cysteinyl Residue in Nitrogenase Catalysis in <i>Azotobacter vinelandii</i>
… one of the Fe atoms 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 …
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Roles of MoFe protein α-274-histidine, α-276-tyrosine and α-277-arginine residues in Azotobacter vinelandii nitrogenase catalysis
… the structural-functional relationship of the protein environment in this region with respect to the FeMo-cofactor, subtle changes were introduced through substitutions using a site-directed mutagenesis and gene-replacement method at α-274-His, α-276-Tyr and α-277-Arg in Azotobacter vinelandii …
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Studies on the structure and function of various nif and nif- associated gene products encoded within the Azotobacter vinelandii nif gene cluster
… roles of the metalloclusters present within the MoFe protein of nitrogenase from Azotobacter vinelandii. A gene replacement strategy was developed for oligonucleotide-directed mutagenesis of these proteins and the resulting biological and biochemical effects of these changes were examined. …
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Spectroscopic investigation of nitrogenase: EPR and MCD studies of the FeMo cofactor and the P-cluster
… Parallel studies were performed on a variant MoFe protein, alpha-195<sup>Gln</sup>, which exhibited different signals from the wild-type suggesting that the substituted amino acid maybe necessary to reach some mechanistic states that the wild-type MoFe protein can reach. Electron transfer …
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Azotobacter vinelandii Nitrogenase: Effect of Amino-Acid Substitutions at the Alpha Gln-191 Residue of the MoFe Protein on Substrate Reduction and CO Inhibition
… in the larger of the two nitrogenase component proteins, called the MoFe protein, and it is strongly implicated as the substrate binding and reduction site. The glutamine-191 residue in the Alpha-subunit of the MoFe protein of A. vinelandii nitrogenase was targeted for substitution because its …
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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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The P Cluster of the Azotobacter vinelandii Nitrogenase Complex: Effects of Substitution at the Cluster-bridging Residue, a-Cys88
… of the role of the nitrogenase component, theMoFe protein, in the catalytic mechanism of biological nitrogen fixation. This dissertation research centers on the role(s) of the P cluster, one of the two unique FeS clusters of the MoFe protein, in the electron transfer mechanism of nitrogenase. …
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The pathway of electron transfer within the nitrogenase complex
… 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 electron transfer was probed by substituting charged residues that, within the model for component protein docking …
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Characterization and site-directed mutagenesis of NifU from Azotobacter vinelandii
… relationship of NifU. Both the Fe protein and the MoFe protein of nitrogenase require processing by additional nif genes including nifM (Fe protein), and nifE, N, B, H, V, and Q (MoFe protein). Two additional genes, nifU and nifS, are required for the maturation of both nitrogenase …
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Biosynthesis of the Nitrogenase FeMo-cofactor from Azotobacter vinelandii: Involvement of the NifEN complex, NifX and the Fe protein
… study was started to characterize the apo-MoFe protein. In this study we used IMAC to purify a poly-histidine-tagged apo-MoFe protein produced by a nifB-deletion mutant of A. vinelandii. Using the poly-histidine fusion approach, apo-MoFe protein was obtained in sufficient quantities for …
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The Biosynthesis and Function of Nitrogenase Metalloclusters
… 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 protein. These metal-complexes play a vital role in enzyme activity during electron transport and substrate reduction. It is known that …
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Mutagenesis of nifE and nifN from Azotobacter vinelandii
… FeMo-co.from a nifEN-products complex to the apo-MoFe protein. A model of metal cluster binding; regions within the nifEN-products is discussed insofar as it relates to the rationale for the targeting of particular amino acids for-substitution. A translational fusion between nifN and lacZ was …
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Development of a Model for the Kinetics and Mechanism of Nitrogenase
… nitrogenase enzyme system is comprised of the MoFe protein and the Fe protein. Interactions between these proteins and nucleotides are crucial to catalysis. An important approach to characterize these interactions is to correlate the kinetics of nitrogenase catalysis to a mechanism based on the …