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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
49
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pubmed:dateCreated |
1999-1-12
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pubmed:abstractText |
We investigated lateral lipid organization in membranes with a lipid composition relevant to neural and retinal membranes [phosphatidylcholine (PC)/phosphatidylethanolamine (PE)/phosphatidylserine (PS)/cholesterol, 4/4/1/1, mol/mol/mol/mol]. The mixed-chain phospholipids contained saturated stearic acid (18:0) in the sn-1 position and the monounsaturated oleic acid (18:1) or polyunsaturated docosahexaenoic acid (22:6) in sn-2. Lateral lipid organization was evaluated by 2H NMR order parameter measurements on stearic acid of all individual types of phospholipids in the mixture and, through a novel approach, two-dimensional NOESY 1H NMR spectroscopy with magic angle spinning (MAS). The docosahexaenoic acid chain order was evaluated from 1H NMR chain signal MAS-sideband intensities. Averaged over all lipids, the cholesterol-induced increase in sn-1 chain order is 2-fold larger in monounsaturated than in polyunsaturated lipids, and the order of both saturated and polyunsaturated hydrocarbon chains increases. Addition of cholesterol increases lipid order in the sequence 18:0-18:1 PE > 18:0-18:1 PC > 18:0-18:1 PS for the monounsaturated and 18:0-22:6 PC >> 18:0-22:6 PE > 18:0-22:6 PS for polyunsaturated mixtures. The variation of order parameters between lipid species suggests that cholesterol induces the formation of lipid microdomains with a headgroup and chain unsaturation-dependent lipid composition. The preferential interaction between cholesterol and polyunsaturated 18:0-22:6 PC, followed by 18:0-22:6 PE and 18:0-22:6 PS, was confirmed by 1H MAS NOESY cross-relaxation rate differences. Furthermore, cholesterol preferentially associates with saturated chains in mixed-chain lipids reflected by higher saturated chain-to-cholesterol cross-relaxation rates. We propose that cholesterol forms PC-enriched microdomains in the polyunsaturated 18:0-22:6 PC/18:0-22:6 PE/18:0-22:6 PS/cholesterol membranes in which the saturated sn-1 chains are preferentially oriented toward the cholesterol molecules.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Cholesterol,
http://linkedlifedata.com/resource/pubmed/chemical/Docosahexaenoic Acids,
http://linkedlifedata.com/resource/pubmed/chemical/Glycerophospholipids,
http://linkedlifedata.com/resource/pubmed/chemical/Lipid Bilayers,
http://linkedlifedata.com/resource/pubmed/chemical/Micelles,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphatidylcholines,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphatidylethanolamines,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphatidylserines,
http://linkedlifedata.com/resource/pubmed/chemical/Phospholipids
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pubmed:status |
MEDLINE
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pubmed:month |
Dec
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pubmed:issn |
0006-2960
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
8
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pubmed:volume |
37
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
17299-308
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:9860844-Cholesterol,
pubmed-meshheading:9860844-Docosahexaenoic Acids,
pubmed-meshheading:9860844-Glycerophospholipids,
pubmed-meshheading:9860844-Lipid Bilayers,
pubmed-meshheading:9860844-Micelles,
pubmed-meshheading:9860844-Nuclear Magnetic Resonance, Biomolecular,
pubmed-meshheading:9860844-Phosphatidylcholines,
pubmed-meshheading:9860844-Phosphatidylethanolamines,
pubmed-meshheading:9860844-Phosphatidylserines,
pubmed-meshheading:9860844-Phospholipids
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pubmed:year |
1998
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pubmed:articleTitle |
Influence of docosahexaenoic acid and cholesterol on lateral lipid organization in phospholipid mixtures.
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pubmed:affiliation |
Laboratory of Membrane Biochemistry and Biophysics, NIAAA, National Institutes of Health, Rockville, Maryland 20852, USA.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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