Grigory I Belogrudov

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The COQ4 gene coding for a component of the coenzyme Q biosynthetic pathway in the yeast Saccharomyces cerevisiae was cloned by a functional complementation of a Q-deficient mutant strain. Yeast coq4 mutant strains harboring the COQ4 gene on either single- or multicopy plasmids acquired the ability to grow on media containing a nonfermentable carbon source,(More)
The electron carriers of the mitochondrial NADH:ubiquinone oxidoreductase (complex I) are contained predominately in two extramembranous subcomplexes, a flavoprotein (FP) and an iron-sulfur protein (IP). FP contains three subunits with molecular masses of 51, 24, and 9 kDa. The 51-kDa subunit carries the NADH binding site and contains FMN and a tetranuclear(More)
Factor B is a subunit of the mammalian ATP synthase complex, whose existence has been controversial. This paper describes the molecular and functional properties of a recombinant human factor B, which when added to bovine submitochondrial particles depleted of their factor B restores the energy coupling activity of the ATP synthase complexes. The mature(More)
The catalytic sector, F1, and the membrane sector, F0, of the mitochondrial ATP synthase complex are joined together by a 45-A-long stalk. Knowledge of the composition and structure of the stalk is crucial to investigating the mechanism of conformational energy transfer between F0 and F1. This paper reports on the near neighbor relationships of the stalk(More)
Coenzyme Q (Q) functions in the electron transport chain of both prokaryotes and eukaryotes. The biosynthesis of Q requires a number of steps involving at least eight Coq polypeptides. Coq5p is required for the C-methyltransferase step in Q biosynthesis. In this study we demonstrate that Coq5p is peripherally associated with the inner mitochondrial membrane(More)
Coupling factor B (FB) is a mitochondrial inner membrane polypeptide that facilitates the energy-driven catalysis of ATP synthesis in animal mitochondria by blocking a proton leak across the membrane. Here, we report the crystal structure of the bovine mitochondrial FB mutant with Gly-3-Glu substitution determined at a resolution of 0.96 A and that of the(More)
Factor B is a water-soluble protein, which is required for the coupled activity of the mitochondrial ATP synthase complex. Specific removal of factor B from well-coupled bovine heart submitochondrial particles (SMP) results in uncoupling and the loss of ATP-driven membrane potential formation and reverse electron transfer from succinate to NAD. Addition of(More)
Since the early studies on the resolution and reconstitution of the oxidative phosphorylation system from animal mitochondria, coupling factor B was recognized as an essential component of the machinery responsible for energy-driven ATP synthesis. At the phenomenological level, factor B was agreed to lie at the interface of energy transfer between the(More)
Treatment of the recombinant bovine factor B with trypsin yielded a fragment (amino acid residues 62-175) devoid of coupling activity. Removal of the N-terminal Trp2-Gly3-Trp4 peptide resulted in a significant loss of coupling activity in the FB(DeltaW)(2)(-W)(4) deletion mutant. Sucrose density gradient centrifugation demonstrated co-sedimentation of(More)
Ectopic expression of coupling factor B in animal cells resulted in altered mitochondrial morphology. Cells expressing factor B fused to green fluorescent protein (GFP) contained fragmented, balloon-shaped or thinned, filamentous mitochondria, terminating at one end with balloon-like structures. Ultrastructural analysis using transmission electron(More)