Deuterium magnetic resonance studies of the interaction of lipids with membrane proteins.
The deuterium magnetic resonance spectra of lipid-protein particles containing cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) isolated from beef heart mitochondria and the specifically deuterated lipid 1-(16,16,16-trideuteropalmitoyl)-2-palmitoleoyl phosphatidylcholine are presented. These reconstituted particles are of uniform lipid and protein content; however, the spectra clearly show two environments characterized by distinctly different residual quadrupolar splittings or order parameters. The less-ordered environment shows a splitting similar to but slightly less than that of the pure lipid alone at a given temperature. The more restricted environment appears to be induced by the presence of the protein. The amount of the restricted lipid is clearly temperature dependent with a 2- to 3-fold decrease in relative amount from 2 to 22 degrees. The rate of exchange of lipid between the free and restricted environments is slower than 10(3)/sec. The significance of these phenomena is discussed.
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003903:Deuterium; D003576:Electron Transport Complex IV; D009682:Magnetic Resonance Spectroscopy; D008563:Membrane Lipids; D008565:Membrane Proteins; D008968:Molecular Conformation; D010713:Phosphatidylcholines; D011487:Protein Conformation; D013696:Temperature
D008563:Membrane Lipids; D008565:Membrane Proteins; D010713:Phosphatidylcholines; D003903:Deuterium; D003576:Electron Transport Complex IV