Premium
Interaction of Polyunsaturated Fatty Acids with Cholesterol: A Role in Lipid Raft Phase Separation
Author(s) -
Wassall Stephen R.,
Shaikh Saame Raza,
Brzustowicz Michael R.,
Cherezov Vadim,
Siddiqui Rafat A.,
Caffrey Martin,
Stillwell William
Publication year - 2004
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200550108
Subject(s) - phosphatidylethanolamine , sphingomyelin , polyunsaturated fatty acid , lipid raft , sterol , phospholipid , raft , cholesterol , fatty acid , chemistry , biochemistry , docosahexaenoic acid , membrane , phosphatidylcholine , organic chemistry , copolymer , polymer
Unequal affinity between lipids has been hypothesized to be a mechanism for the formation of microdomains/rafts in membranes. Our studies focus upon the interaction of cholesterol with polyunsaturated fatty acid (PUFA)‐containing phospholipids. They support the proposal that steric incompatibility of the rigid steroid moiety for highly disordered PUFA chains, in particular docosahexaenoic acid (DHA), provides a sensitive trigger for lateral segregation of lipids into PUFA‐rich/sterol‐poor and PUFA‐poor/sterol‐rich regions. Solid state 2 H NMR and x‐ray diffraction (XRD) demonstrate that the solubility of cholesterol is reduced in 1‐palmitoyl‐2‐docosahexaenoyl‐phosphatidylethanolamine (16‐0:22:6PE) bilayers. In mixed membranes of phosphatidylethanolamine (PE) with the lipid raft forming molecules egg sphingomyelin (SM) and cholesterol, diminished affinity of the sterol for 16:0‐22:6PE relative to 1‐palmitoyl‐2‐oleoylphosphatidylethanolamine (16:0‐18:1PE) is identified by 2 H NMR order parameters and detergent extraction. Phase separation of the PUFA‐containing phospholipid from SM/cholesterol rafts is the implication, which may be associated with the myriad of health benefits of dietary DHA.