Location of terminal methyl groups of acyl chains in the bilayer of unilamellar phosphatidylcholine liposomes: a 13C-NMR study.
The spin-lattice 13C-NMR relaxation time T1 of carbons in egg yolk phosphatidylcholine (EYPC) unilamellar liposomes was measured at 15 MHz, 25 MHz and 75 MHz in the presence of diamagnetic La3+ and paramagnetic Gd3+ ions. Supposing formation of ML2 complexes (where M is the metal ion and L the lipid) and using a simplified Solomon-Bloembergen-Morgan equation, a value of less than r-3IS greater than 2 = 0.1880 +/- 0.0005 nm-6 was obtained for C omega carbon of lipid chains, where rIS is the distance of Gd3+ unpaired electron and C omega nucleus, and angle brackets denote a weighted average. This value may serve as the basis for testing the application of statistical mechanics to lipid chain conformation and chain terminal group distribution in lipid bilayers.
Uhríková
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Faculty of Pharmacy, J.A. Comenius University, Bratislava, Czechoslovakia.
Balgavý
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P
D000818:Animals; D004530:Egg Yolk / Q000032:analysis; D008081:Liposomes / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D010713:Phosphatidylcholines / Q000032:analysis*
D008081:Liposomes; D010713:Phosphatidylcholines