A CHEMICAL AND SPECTROSCOPIC STUDY OF FERREDOXIN I FROM AZOTOBACTER VINELANDII.
Item
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Title
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A CHEMICAL AND SPECTROSCOPIC STUDY OF FERREDOXIN I FROM AZOTOBACTER VINELANDII.
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Identifier
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AAI8708304
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identifier
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8708304
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Creator
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MALIKAYIL, JOY ANTONY.
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Contributor
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William Sweeney
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Date
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1987
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Biochemistry
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Abstract
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Ferredoxin I of Azotobacter vinelandii is an iron sulfur protein containing one 4Fe-S cluster and one 3Fe-3S cluster. The structure and geometry of the 3Fe cluster is under dispute. The X-ray crystal structure of the protein describes the 3Fe cluster as a planar 3Fe-3S cluster in which one of the iron atoms is ligated to a solvent accessible oxoligand, presumably from water or hydroxide (Ghosh et al., (1982) J. Mol. Biol. 158: 73-109). Efforts to displace the oxoligand were unsuccessful even when the protein was demonstrably denatured in 80% (V/V) dimethyl sulfoxide. In addition, comparison of the electron spin echo envelopes for H(,2)O and D(,2)O-equilibrated samples of ferredoxin I showed only a slight deuterium modulation, far less than would be expected were water to be bound as an iron ligand. These results do not support the presence of a solvent accessible oxoligand to the 3Fe center as described in the X-ray crystal structure.;The latter part of the thesis describes studies conducted in efforts to characterize the hyperfine-shifted resonances in the proton magnetic resonance spectrum of ferredoxin I. A. vinelandii was grown on synthetic media that contained isotopically labelled cystine as the only sulfur source. In independent experiments ferredoxin I was isolated from organism that was grown on such medium that contained alpha-('2)H-dl-cystine, beta-('2)H-dl-cystine, or beta-('13)C-dl-cystine. However, ferredoxins isolated from these media were devoid of the corresponding isotopic labels. Thus the experiments designed to characterize the hyperfine-shifted resonances of ferredoxin I were unsuccessful.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Biochemistry
