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Phospholipid composition and organization of cytochrome c oxidase preparations as determined by 31P-nuclear magnetic resonance

Seelig, A. and Seelig, J.. (1985) Phospholipid composition and organization of cytochrome c oxidase preparations as determined by 31P-nuclear magnetic resonance. Biochimica et biophysica acta, Vol. 815, H. 2. S. 153-158.

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Official URL: http://edoc.unibas.ch/dok/A5258495

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Abstract

The molecular organization as well as the composition of the phospholipids in cytochrome c oxidase preparations (bovine heart) were investigated by 31P-nuclear magnetic resonance. In the so-called 'lipid-rich' preparation the lipids were found to form a fluid bilayer around the enzyme since the 31P-NMR spectrum was characteristic of a fast, axially symmetric motion of the phosphate groups with a chemical shift anisotropy of delta sigma = -45 ppm. In contrast, the 'lipid-depleted' cytochrome c oxidase gave rise to a broader spectrum where the motion of the phospholipids was no longer axially symmetric. Nevertheless, the total width of the spectrum was still considerably narrower than observed for immobilized phospholipids in solid crystals. Both enzyme preparations were dissolved in 1% detergent solution and used for high-resolution 31P-NMR spectroscopy. Narrow lines of about 20 Hz linewidth were obtained for both types of enzyme preparations, and well-resolved resonances could be assigned to cardiolipin, phosphatidylethanolamin and phosphatidylcholine. The major differences between lipid-rich and lipid-depleted cytochrome c oxidase were the absolute amount of phospholipid associated with the protein and the relative contribution of the individual lipid classes to the 31P-NMR spectrum. For lipid-rich cytochrome c oxidase about 130 molecules phospholipid were bound per enzyme (approx. 11 cardiolipins, 54 phosphatidylethanolamines and 64 phosphatidylcholines). For lipid-depleted cytochrome c oxidase only 6-18 lipids were bound per enzyme (1 or 2 cardiolipins, 3-8 phosphatidylethanolamines and 2-8 phosphatidylcholines). In contrast to earlier suggestions that cardiolipin is the only remaining lipid in lipid-depleted cytochrome c oxidase, the 31P-NMR studies demonstrate that all three lipids remain associated with the protein.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Biophysical Chemistry (Seelig A)
05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Biophysical Chemistry (Seelig J)
UniBasel Contributors:Seelig, Joachim and Seelig-Löffler, Anna
Item Type:Article, refereed
Bibsysno:Link to catalogue
Publisher:Elsevier
ISSN:0006-3002
Note:Publication type according to Uni Basel Research Database: Journal article
Identification Number:
Last Modified:14 Sep 2012 06:48
Deposited On:22 Mar 2012 13:20

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