Recent advances in structure-functional studies of mitochondrial factor B.
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 respiratory chain and the ATP synthase complex. However, biochemical characterization of the factor B polypeptide has proved difficult. It was not until 1990 that the N-terminal amino acid sequence of bovine mitochondrial factor B was reported, which followed, a decade later, by the report describing the amino acid sequence of full-length human factor B and its functional characterization. The present review summarizes the recent advances in structure-functional studies of factor B, including its recently determined crystal structure at 0.96 A resolution. Ectopic expression of human factor B in cultured animal cells has unexpectedly revealed its role in shaping mitochondrial morphology. The supramolecular assembly of ATP synthase as dimer ribbons at highly curved apices of the mitochondrial cristae was recently suggested to optimize ATP synthesis under proton-limited conditions. We propose that the binding of the ATP synthase dimers with factor B tetramers could be a means to enhance the efficiency of the terminal step of oxidative phosphorylation in animal mitochondria.
Belogrudov
Grigory I
GI
West Los Angeles Veterans Administration Medical Center, 11301 Wilshire Blvd., Los Angeles, CA 90073, USA. gbelo@ucla.edu
D025181:ATP Synthetase Complexes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D000818:Animals; D002417:Cattle; D002460:Cell Line; D004579:Electron Transport / Q000502:physiology; D006801:Humans; D008928:Mitochondria / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D025261:Mitochondrial Proton-Translocating ATPases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010085:Oxidative Phosphorylation; D010086:Oxidative Phosphorylation Coupling Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020836:Protein Structure, Quaternary / Q000502:physiology; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
D010086:Oxidative Phosphorylation Coupling Factors; D000255:Adenosine Triphosphate; D025181:ATP Synthetase Complexes; C032410:coupling factor B; D025261:Mitochondrial Proton-Translocating ATPases