Kollmitzer Benjamin, Heftberger Peter, Rappolt Michael, Pabst Georg
Institute of Molecular Biosciences, Biophysics Division, University of Graz, Austria.
Institute of Inorganic Chemistry, Graz University of Technology, Austria ; School of Food Science and Nutrition, University of Leeds, UK.
Soft Matter. 2013 Dec 7;9(45):10877-10884. doi: 10.1039/C3SM51829A.
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). Spontaneous curvatures of bilayer forming lipids were estimated by adding controlled amounts to a H 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 values are closer to zero. Interestingly, a significant positive value was retrieved for DPPC. We further determined the temperature dependence of the spontaneous curvatures () in the range from 15 to 55 °C, resulting in a quite narrow distribution of -1 to -3 × 10 (nm °C) 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.
利用小角X射线散射（SAXS）对反相六角相（H）进行研究，获得了胆固醇、二油酰磷脂酰乙醇胺（DOPE）、单棕榈酰磷脂酰乙醇胺（POPE）、二油酰磷脂酰胆碱（DOPC）、二棕榈酰磷脂酰胆碱（DPPC）、二硬脂酰磷脂酰胆碱（DSPC）、棕榈酰油酰磷脂酰胆碱（POPC）、硬脂酰油酰磷脂酰胆碱（SOPC）和鸡蛋鞘磷脂的单层自发曲率。按照先前建立的方案，通过向形成H相的模板中添加可控量的物质，估算形成双层的脂质的自发曲率。发现磷脂酰乙醇胺和胆固醇的自发曲率至少比磷脂酰胆碱的自发曲率负两倍，而磷脂酰胆碱的值更接近零。有趣的是，DPPC的自发曲率值为正。我们进一步测定了15至55°C范围内自发曲率（）的温度依赖性，结果表明大多数研究的脂质的自发曲率分布相当窄，为-1至-3×10（nm/°C）。这些数据使我们能够估算出显示液相有序/液相无序相共存的三元脂质混合物的单层自发曲率。我们报告了DSPC/DOPC/胆固醇、DPPC/DOPC/胆固醇和鞘磷脂/POPC/胆固醇的自发曲率相图，并讨论了对蛋白质插入和线张力的影响。
