Interpretation of 100- and 360-MHz proton magnetic resonance spectra of retinal rod outer segment disk membranes
| Autor: | George P. Miljanich, Michael F. Brown, Edward A. Dratz |
|---|---|
| Rok vydání: | 1977 |
| Předmět: |
Magnetic Resonance Spectroscopy
biology Bilayer Vesicle Cell Membrane Phospholipid Temperature Resonance Biochemistry NMR spectra database chemistry.chemical_compound Crystallography Membrane Lipids Nuclear magnetic resonance Membrane chemistry Rhodopsin Liposomes Proton NMR biology.protein Animals Cattle Photoreceptor Cells Mathematics Phospholipids |
| Zdroj: | Biochemistry. 16(12) |
| ISSN: | 0006-2960 |
| Popis: | Well resolved proton nuclear magnetic resonance ('H NMR) spectra of bovine retinal rod outer segment (ROS) disk membranes have been obtained at 100 and 360 MHz. The resolved IH resonances of the ROS membranes are due to phospholipids, with little contribution from rhodopsin. The spectra of both the ROS membranes and bilayer vesicles pre- pared from purified ROS phospholipids (liposomes) appear to represent a superposition of relatively sharp resonance components and a broad, underlying background. The distri- bution between sharp and broad spectral components is sen- sitive to sonication and temperature. The percentage of choline methyl protons which are resolved in the ROS membrane spectra as sharp resonance components increases from ap- proximately 35 to 100% and the average of the lipid hydro- carbon chain protons from approximately 20 to 40% over the Nuclear magnetic resonanie (NMR)~ has been used to elucidate details of motion (Horwitz et al., 1972; 1973b; Levine et al., 1972), phase behavior (Chapman, 1975), and asymmetry (Michaelson et al., 1974) in pure and mixed phospholipid bi- layer membranes. In addition, well resolved NMR spectra have been obtained of several natural membranes (see, e.g., Lee et al., 1974a; Davis et al., 1976). A relatively simple membrane system which appears to be particularly amenable to magnetic resonance studies is the rod outer segment (ROS) disk mem- brane from the vertebrate retina (for reviews see Hagins, 1972; Daemen, 1973; Hubbell, 1975; Ebrey and Honig, 1975; Dratz, 1977). A single protein, rhodopsin, comprises at least 85% of the total protein content. The ROS phospholipids are partic- ularly rich in polyunsaturated fatty acids, with docosahexenoic acid (C22:6w3) comprising at least 3 1-37% of the total fatty acid composition of bovine ROS disk membranes* (Nielson et al., 1970; Anderson and Sperling, 1971). The visual pigment rhodopsin rotates and translates freely in the ROS disk |
| Databáze: | OpenAIRE |
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