Membrane topography of the subunits of ubiquinol-cytochrome-c oxidoreductase of Saccharomyces cerevisiae. The 14-kDa and the 11-kDa subunits face opposite sides of the mitochondrial inner membrane.
The topology of the subunits of ubiquinol-cytochrome-c oxidoreductase of the yeast Saccharomyces cerevisiae has been determined using a digitonin/proteinase K assay. With this assay we were able selectively to disrupt the mitochondrial membranes and to identify the subunits which became proteinase-K sensitive after disruption of either the outer or both outer and inner membranes. This approach confirmed previous indications for the localization of the core I protein, cytochrome c1, cytochrome b, the FeS protein and the 17-kDa subunit, while it also provided direct evidence for the site of accessibility to proteinase K of the 14-kDa and 11-kDa subunits. The 14-kDa subunit faces the mitochondrial matrix and the 11-kDa subunit faces the intermembrane space.
Hemrika
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E.C. Slater Institute for Biochemical Research, University of Amsterdam, The Netherlands.
Berden
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JA
D002462:Cell Membrane / Q000201:enzymology; D003573:Cytochrome b Group / Q000032:analysis; D003574:Cytochrome c Group / Q000032:analysis; D004072:Digitonin; D014450:Electron Transport Complex III / Q000032:analysis / Q000737:chemistry* / Q000235:genetics; D019286:Endopeptidase K; D005649:Fumarate Hydratase / Q000032:analysis; D007425:Intracellular Membranes / Q000201:enzymology; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D012697:Serine Endopeptidases
D003573:Cytochrome b Group; D003574:Cytochrome c Group; D012697:Serine Endopeptidases; D019286:Endopeptidase K; D005649:Fumarate Hydratase; D014450:Electron Transport Complex III; D004072:Digitonin