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RESEARCH PRODUCT
The Influence of Hydrogen Bonding on Sphingomyelin/Colipid Interactions in Bilayer Membranes
Olli T. PentikäinenMd. Abdullah Al SazzadNiklas Z. JänttiJ. Peter SlotteTomokazu Yasudasubject
0301 basic medicineCeramideDouble bondStereochemistryLipid BilayersBiophysicsPhospholipidOleic AcidsPalmitic AcidsCholesterol analogCeramides03 medical and health scienceschemistry.chemical_compoundLipid bilayerchemistry.chemical_classificationMembranesHydrogen bondBilayerfungita1182technology industry and agricultureHydrogen BondingSphingomyelins030104 developmental biologychemistrylipids (amino acids peptides and proteins)Sphingomyelindescription
The phospholipid acyl chain composition and order, the hydrogen bonding, and properties of the phospholipid headgroup all influence cholesterol/phospholipid interactions in hydrated bilayers. In this study, we examined the influence of hydrogen bonding on sphingomyelin (SM) colipid interactions in fluid uni- and multilamellar vesicles. We have compared the properties of oleoyl or palmitoyl SM with comparable dihydro-SMs, because the hydrogen bonding properties of SM and dihydro-SM differ. The association of cholestatrienol, a fluorescent cholesterol analog, with oleoyl sphingomyelin (OSM) was significantly stronger than its association with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, in bilayers with equal acyl chain order. The association of cholestatrienol with dihydro-OSM, which lacks a trans double bond in the sphingoid base, was even stronger than the association with OSM, suggesting an important role for hydrogen bonding in stabilizing sterol/SM interactions. Furthermore, with saturated SM in the presence of 15 mol % cholesterol, cholesterol association with fluid dihydro-palmitoyl SM bilayers was stronger than seen with palmitoyl SM under similar conditions. The different hydrogen bonding properties in OSM and dihydro-OSM bilayers also influenced the segregation of palmitoyl ceramide and dipalmitoylglycerol into an ordered phase. The ordered, palmitoyl ceramide-rich phase started to form above 2 mol % in the dihydro-OSM bilayers but only above 6 mol % in the OSM bilayers. The lateral segregation of dipalmitoylglycerol was also much more pronounced in dihydro-OSM bilayers than in OSM bilayers. The results show that hydrogen bonding is important for sterol/SM and ceramide/SM interactions, as well as for the lateral segregation of a diglyceride. A possible molecular explanation for the different hydrogen bonding in SM and dihydro-SM bilayers is presented and discussed.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2016-01-19 |