The effect of cytochrome c oxidase on lipid polymorphism of model membranes containing cardiolipin.
The effect of cytochrome c oxidase incorporation on the lipid polymorphism of the cardiolipin-Ca2+ system was investigated by 31P NMR and freeze-fracture electron microscopy. The integral membrane protein has a stabilizing effect on the bilayer organization of cardiolipin, in that it inhibits the Ca2+-induced HII phase formation of this lipid for Ca2+/cardiolipin molar ratios of 1-10. At a Ca2+/cardiolipin molar ratio of 25, about 80% of the lipid is organized in the HII phase and a structural phase separation occurs between the cardiolipin-Ca2+ complex organized in the hexagonal HII phase without protein and bilayer structures with incorporated protein.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002308:Cardiolipins / Q000378:metabolism*; D002417:Cattle; D003576:Electron Transport Complex IV / Q000378:metabolism*; D005614:Freeze Fracturing; D008051:Lipid Bilayers; D050356:Lipid Metabolism; D009682:Magnetic Resonance Spectroscopy; D008566:Membranes / Q000648:ultrastructure; D008567:Membranes, Artificial; D008854:Microscopy, Electron; D011110:Polymorphism, Genetic
D002308:Cardiolipins; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D003576:Electron Transport Complex IV; D002118:Calcium