Phase studies of model biomembranes: Complex behavior of DSPC/DOPC/Cholesterol
| Autor: | Paul Klawitter, Jing Wu, Greg Costanza, J. Zhao, Gerald W. Feigenson, Grace T. Huang, Frederick A. Heberle, Thalia T. Mills |
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| Rok vydání: | 2007 |
| Předmět: |
Phase transition
Liquid ordered phase Lipid Bilayers Biophysics Analytical chemistry Ternary phase diagram 010402 general chemistry 01 natural sciences Biochemistry Article Phase Transition Bilayer phase separation 03 medical and health sciences chemistry.chemical_compound X-Ray Diffraction Phase (matter) Fluorescence Resonance Energy Transfer Fluorescence microscope Liquid-disordered phase Lipid bilayer Lipid rafts 030304 developmental biology Phase diagram 0303 health sciences Vesicle Liquid-ordered phase Cell Biology 0104 chemical sciences Cholesterol Spectrometry Fluorescence chemistry Phosphatidylcholines lipids (amino acids peptides and proteins) Perylene |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 1768:2764-2776 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/j.bbamem.2007.07.008 |
| Popis: | We have undertaken a series of experiments to examine the behavior of individual components of cell membranes. Here we report an initial stage of these experiments, in which the properties of a chemically simple lipid mixture are carefully mapped onto a phase diagram. Four different experimental methods were used to establish the phase behavior of the 3-component mixture DSPC/DOPC/chol: (1) confocal fluorescence microscopy observation of giant unilamellar vesicles, GUVs; (2) FRET from perylene to C20:0-DiI; (3) fluorescence of dilute dyes C18:2-DiO and C20:0-DiI; and (4) wide angle X-ray diffraction. This particular 3-component mixture was chosen, in part, for a high level of immiscibility of the components in order to facilitate solving the phase behavior at all compositions. At 23 degrees C, a large fraction of the possible compositions for this mixture give rise to a solid phase. A region of 3-phase coexistence of {Lalpha+Lbeta+Lo} was detected and defined based on a combination of fluorescence microscopy of GUVs, FRET, and dilute C20:0-DiI fluorescence. At very low cholesterol concentrations, the solid phase is the tilted-chain phase Lbeta'. Most of the phase boundaries have been determined to be within a few percent of the composition. Measurements of the perturbations of the boundaries of this accurate phase diagram could serve as a means to understand the behaviors of a range of added lipids and proteins. |
| Databáze: | OpenAIRE |
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