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R I Gvozdev

Publications and source records attributed to R I Gvozdev.

At least 19 recordsLinked to original sources
PubMed1995

Flavin-dependent alcohol oxidase from the yeast Pichia pinus. Spatial localization of the coenzyme FAD in the protein structure: hot-tritium bombardment and ESR experiments.

The spatial localization of the coenzyme FAD in the quaternary structure of the alcohol oxidase from the yeast Pichia pinus was studied by tritium planigraphy and ESR methods. In the present paper we measured the specific radioactivity of FAD labelled as a part of the alcohol oxidase complex. The specific-radioactivity ratio for two FAD portions (FMN and AMP) was calculated. ESR experiments show 4 A (0.4 nm) to be the depth of immersion of paramagnetic isoalloxazines into alcohol oxidase octamer molecules. It is suggested that FAD molecules are bound to the surface of the octamer, rather than to the subunit interfaces. The orientation of the prosthetic group FAD in the alcohol oxidase protein is discussed.

Adenosine Monophosphate↗
PubMed1985

Electron microscopy of the Mo-Fe-protein from Azotobacter vinelandii nitrogenase.

The quaternary structure of the Mo-Fe-protein from Azotobacter vinelandii has been studied by electron microscopy. A model of the molecule of the Mo-Fe-protein has been proposed: two alpha subunits are displaced relative to two beta subunits along a twofold axis, so the molecule can be characterized by the point-group pseudosymmetry 222. Computer averaging of the images showed that one of the projections of the molecule could be characterized by twofold rotational symmetry. Micrographs of nitrogenase recombined complex (Mo-Fe-protein + Fe-protein) have been obtained. They showed particles close in size and form to the Mo-Fe-protein molecule. Therefore, it has been proposed that the Fe-protein could be situated in the central cavity of Mo-Fe-protein.

Azotobacter↗
PubMed1982

[Role of CO-binding cytochrome c in enzymatic oxidation of methane by the bacterium Methylococcus capsulatus].

The cytochrome c spectrally related to cco cytochromes has been isolated and purified from the methane-oxidizing bacterium Methylococcus capsulatus. The cytochrome binds CO but does not bind other substrates of methane monooxygenase, does not activate the methane monooxygenase reaction and is not a component of methane monooxygenase. In the methanol dehydrogenase enzymatic system cytochrome cco functions as electron acceptor. A possible role of cytochrome cco as electron carrier intermediate in the sequence of the dehydrogenase and oxidase enzymatic systems of M. capsulatus is discussed.

Carbon Monoxide↗
PubMed1976

[Isotopic effect in enzymatic oxidation of methane].

The isotopic effect during oxidation of methane and deuteromethane by a suspension of Methylomonas rubrum cells, for which methane is the only source of carbon, was observed. The rate of CH4 oxidation is 12.5 times higher than that of CH4 oxidation. It is demonstrated that CD4 is a competitive inhibitor of CH4 oxidation. The results obtained suggest that the disruption of the C-H bond is the limiting step of enzymatic oxidation of methane.

Deuterium↗
PubMedDate not supplied

Structure and mechanism of catalytic action of active sites of nitrogenase.

A review of the data on the macromolecular structure of nitrogenase and its individual fragments, the electronic structure of iron- and molybdenum-containing components of the active site, and the functional groups of the ATPase site of the enzyme is given. Reactions of N2 reduction, ATP hydrolysis, and H2 evolution, inhibitory processes, and electron transport reactions catalyzed by the enzyme are analyzed within the framework of a general kinetic model. The results of an investigation of the location of the iron-containing cluster system of electron transport, the ATPase site, and the N2-binding and reducing site on the nitrogenase macro-molecule with the aid of a new complex approach including methods of spin, luminescent, and electron-dense labeling are described. On the basis of a number of physicochemical and kinetic data a model of the structure and mechanism of action of the active site of nitrogenase is proposed, which assumes four-step electron transfer from an external reducing agent along the chain of ferredoxin-like iron-containing clusters of the enzyme and an increase in the reducing potential of the iron clusters through the energy of ATP hydrolysis and four-electron reduction in a binuclear molybdenum-containing complex.

Adenosine Triphosphatases↗
PubMedDate not supplied

[Estimation of the distance between the iron-sulfur cluster of Fe-protein and the nearest iron-sulfur cluster of Mo-Fe-protein of nitrogenase on the basis of the inductive-resonance theory of energy transfer].

The distance between fluorescein mercuric acetate (FMA), attached to the HS-group of Fe- and Mo-Fe-protein, and the nearest iron-sulphur cluster (ISC) was determined. For Fe-protein the distance was 18--20 A and for Mo-Fe-protein 12--14 A. The distance between Fe-protein FMA and the nearest Mo-protein ISC determined by complementation of the labelled Fe-protein and native Mo-Fe-protein was 14--16 A. The distance between MO-OFe-protein ISC and complement Fe-protein ISC was 18--20 A. A te-protein ISC permitted to suppose that the electron was transfered from Fe-protein ISC to Mo-Fe-protein ISC by the contact of the ISC or with the help of ATP molecule.

Binding Sites↗