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Sphingomyelin analogs with branched N-acyl chains: The position of branching dramatically affects acyl chain order and sterol interactions in bilayer membranes
- Source :
-
BBA: Biomembranes . Oct2010, Vol. 1798 Issue 10, p1987-1994. 8p. - Publication Year :
- 2010
-
Abstract
- Abstract: Sphingolipids have been found to have single methyl branchings both in their long-chain base and in their N-linked acyl chains. In this study we determined how methyl-branching in the N-linked acyl chain of sphingomyelin (SM) affected their membrane properties. SM analogs with a single methyl-branching at carbon 15 (of a 17:0 acyl chain; anteiso) had a lower gel–liquid transition temperature as compared to an iso-branched SM analog. Phytanoyl SM (methyls at carbons 3, 7, 11 and 15) as well as a SM analog with a methyl on carbon 10 in a hexadecanoyl chain failed to show a gel–liquid transition above 10°C. Only the two distally branched SM analogs (iso and anteiso) formed ordered domains with cholesterol in a 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) bilayer. However, domains formed by the branched SM analogs appeared to contain less sterol when compared to palmitoyl SM (PSM) as the saturated phospholipid. Sterol-enriched domains formed by the anteiso SM analog were also less stable against temperature than domains formed by PSM. Both the 10-methyl and phytanoyl SM analogs failed to form sterol-enriched domains in the POPC bilayer. Acyl chain branching weakened SM/sterol interactions markedly when compared to PSM, as also evidenced from the decreased affinity of cholestatrienol to bilayers containing branched SM analogs. Our results show that methyl-branching weakened intermolecular interactions in a position-dependent manner. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00052736
- Volume :
- 1798
- Issue :
- 10
- Database :
- Academic Search Index
- Journal :
- BBA: Biomembranes
- Publication Type :
- Academic Journal
- Accession number :
- 53052911
- Full Text :
- https://doi.org/10.1016/j.bbamem.2010.07.006