These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Interaction of cholesterol with a docosahexaenoic acid-containing phosphatidylethanolamine: trigger for microdomain/raft formation?
    Author: Shaikh SR, Cherezov V, Caffrey M, Stillwell W, Wassall SR.
    Journal: Biochemistry; 2003 Oct 21; 42(41):12028-37. PubMed ID: 14556634.
    Abstract:
    Docosahexaenoic acid (DHA, 22:6) containing phospholipids have been postulated to be involved in promoting lateral segregation within membranes into cholesterol- (CHOL-) rich and CHOL-poor lipid microdomains. Here we investigated the specific molecular interactions of phospholipid bilayers composed of 1-[(2)H(31)]palmitoyl-2-docosahexaenoyl-sn-glycero-3-phosphoethanolamine (16:0-22:6PE-d(31)) or 1-[(2)H(31)]palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (16:0-18:1PE-d(31)) with equimolar CHOL using solid-state (2)H NMR spectroscopy and low- and wide-angle X-ray diffraction (XRD). Moment analysis of (2)H NMR spectra obtained as a function of temperature reveals that the main chain melting transition and the lamellar-to-inverted hexagonal (H(II)) phase transition of 16:0-22:6PE-d(31) remain in the presence of equimolar CHOL, whereas addition of equimolar CHOL essentially obliterates the gel-to-liquid crystalline transition of 16:0-18:1PE-d(31). (2)H NMR order parameter measurements show that the addition of equimolar CHOL in the lamellar liquid crystalline phase causes a smaller increase in order for the perdeuterated sn-1 chain by 22% for 16:0-22:6PE-d(31) as opposed to 33% for 16:0-18:1PE-d(31). XRD experiments determined markedly lower solubility of 32 +/- 3 mol % for CHOL in 16:0-22:6PE bilayers in contrast to the value of approximately 51 mol % for 16:0-18:1PE. Our findings provide further evidence that cholesterol has a low affinity for DHA-containing phospholipids and that this reduced affinity may serve as a mechanism for triggering the formation of lipid microdomains such as rafts.
    [Abstract] [Full Text] [Related] [New Search]