Monolayer spontaneous curvature of raft-forming membrane lipids.
basic_science · Level V
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- Record sourced from PubMed, PMID 24672578.
- Also identified by PMC identifier 3963256.
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Abstract
Monolayer spontaneous curvatures for cholesterol, DOPE, POPE, DOPC, DPPC, DSPC, POPC, SOPC, and egg sphingomyelin were obtained using small-angle X-ray scattering (SAXS) on inverted hexagonal phases (H<sub>II</sub>). Spontaneous curvatures of bilayer forming lipids were estimated by adding controlled amounts to a H<sub>II</sub> forming template following previously established protocols. Spontaneous curvatures of both phosphatidylethanolamines and cholesterol were found to be at least a factor of two more negative than those of phosphatidylcholines, whose <i>J</i><sub>0</sub> values are closer to zero. Interestingly, a significant positive <i>J</i><sub>0</sub> value was retrieved for DPPC. We further determined the temperature dependence of the spontaneous curvatures <i>J</i><sub>0</sub>(<i>T</i>) in the range from 15 to 55 °C, resulting in a quite narrow distribution of -1 to -3 × 10<sup>-3</sup> (nm °C)<sup>-1</sup> for most investigated lipids. The data allowed us to estimate the monolayer spontaneous curvatures of ternary lipid mixtures showing liquid ordered/liquid disordered phase coexistence. We report spontaneous curvature phase diagrams for DSPC/DOPC/Chol, DPPC/DOPC/Chol and SM/POPC/Chol and discuss effects on protein insertion and line tension.