Distribution of charge on photoreceptor disc membranes and implications for charged lipid asymmetry.
A novel spin labeling technique is used to determine both the inner and outer surface potentials of isolated rod outer segment disc membranes and of reconstituted membranes containing rhodopsin with defined lipid compositions. It is shown that these potentials can be accounted for in a consistent manner by the accepted model of rhodopsin, the known lipid composition, and the Gouy-Chapman theory, provided the charged lipid is asymmetric in the membrane, with approximately 75% on the external surface.
Tsui
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FC
Jules Stein Eye Institute, University of California, Los Angeles 90024-1771.
Sundberg
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Hubbell
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D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000502:physiology; D004578:Electron Spin Resonance Spectroscopy; D008081:Liposomes; D008563:Membrane Lipids / Q000502:physiology*; D008564:Membrane Potentials; D008954:Models, Biological; D008969:Molecular Sequence Data; D010713:Phosphatidylcholines; D010786:Photoreceptor Cells / Q000502:physiology*; D011487:Protein Conformation; D012168:Retinal Pigments / Q000502:physiology*; D012243:Rhodopsin / Q000502:physiology*; D012374:Rod Cell Outer Segment / Q000502:physiology*
D008081:Liposomes; D008563:Membrane Lipids; D010713:Phosphatidylcholines; D012168:Retinal Pigments; D012243:Rhodopsin