Spin-label studies of lipid-protein interactions in (Na+,K+)-ATPase membranes from rectal glands of Squalus acanthias.

Journal article

Lipid-protein interactions in (Na+,K+)-ATPase-rich membranes from the rectal gland of Squalus acanthias have been studied by using spin-labeled lipids in conjunction with electron spin resonance (ESR) spectroscopy. Lipid-protein associations are revealed by the presence of a second component in the ESR spectra of the membranes in addition to a component which corresponds very closely to the ESR spectra obtained from dispersions of the extracted membrane lipids. This second component corresponds to spin-labeled lipids whose motion is very significantly restricted relative to that of the fluid lipids in the membrane or the lipid extract. A stoichiometry of approximately 66 lipids per 265 000-dalton protein is found for the motionally restricted component of those spin-labeled lipids (e.g., phosphatidylcholine) which show least specificity for the protein. This corresponds approximately to the number of lipids which may be accommodated within the first shell around the alpha 2 beta 2 protein dimer. A selectivity of the various spin-labeled lipids for the motionally restricted component associated with the protein is found in the following order: cardiolipin greater than phosphatidylserine approximately stearic acid greater than or equal to phosphatidic acid greater than phosphatidylglycerol approximately phosphatidylcholine approximately phosphatidylethanolamine approximately androstanol.

Authors: Esmann, M; Watts, A; Marsh, D

• Journal: Biochemistry
• Volume: 24
• Issue: 6
• Pages: 1386-1393
• Publication date: 1985-03-01
• DOI: 10.1021/bi00327a016
• EISSN: 1520-4995
• ISSN: 0006-2960
• Language: English
• Keywords: Sodium-Potassium-Exchanging ATPase; Salt Gland; Mathematics; Membrane Lipids; Dogfish; Animals; Rectum; Membrane Proteins; Electron Spin Resonance Spectroscopy; Cold Temperature