Characterization of a membrane fragment of respiratory chain complex I from Neurospora crassa. Insights on the topology of the ubiquinone-binding site.
1. A membrane fragment of complex I from the fungus Neurospora crassa was isolated by immunoprecipitation from alkaline-extracted mitochondrial membranes. 2. Analysis of the polypeptide composition of this hydrophobic domain of complex I has brought insights on the topology of two subunits of the enzyme, namely the 20.8 and 9.3 kDa components. 3. Our results indicate that the ubiquinone-binding site of complex I resides in the interface of the peripheral and membrane arms of the enzymes. The significance of these findings are discussed.
Azevedo
J E
JE
Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Portugal.
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D001665:Binding Sites; D007425:Intracellular Membranes / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology; D008956:Models, Chemical; D008970:Molecular Weight; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D009492:Neurospora crassa / Q000201:enzymology*; D011487:Protein Conformation; D014451:Ubiquinone / Q000378:metabolism*
D014451:Ubiquinone; D016660:NAD(P)H Dehydrogenase (Quinone)