Lateral Diffusion and Molecular Interaction in a Bilayer Membrane Consisting of Partially Fluorinated Phospholipids
Lateral Diffusion and Molecular Interaction in a Bilayer Membrane Consisting of Partially Fluorinated Phospholipids
复制标题
部分氟化磷脂双层膜中的横向扩散和分子相互作用
DOI：
10.1021/acs.langmuir.6b02874
复制
发表时间：
2016
期刊：
影响因子：
3.9
通讯作者：
R. Tero
中科院分区：
文献类型：
--
作者：
Y. Okamoto;T. Motegi;K. Morita;T. Takagi;H. Amii;T. Kanamori;M. Sonoyama;R. Tero
由于碳氟化合物的生物惰性，含氟脂质和表面活性剂是用于膜蛋白提取和重组的有吸引力的仿生材料。我们研究了部分氟化磷脂（F4-DMPC）的基本物理性质，如相变、面积热膨胀和侧向脂质扩散，以自由体积理论为基础定量评价F4-DMPC在疏水区的分子间相互作用。对F4-DMPC的支撑脂质双层（SLB）的荧光显微镜观察表明，液晶相和凝胶相之间的相变发生在5 °C，并且面积热膨胀系数在相变温度附近与温度无关。我们在SiO2/Si衬底上对F4-DMPC-SLB进行了单粒子跟踪，以测量扩散系数及其温度依赖性。横向脂质扩散的表观活化能（E′a）是分子间相互作用的指标，对于F4-DMPC为39.1 kJ/mol，对于作为对照的非氟化1，2-二油酰基-sn-甘油-3-磷酸胆碱为48.2 kJ/mol。与非氟化磷脂酰胆碱中的酰基链物种以及在双层膜中加入胆固醇和乙醇所引起的差异相比，E ′ a的差异为9 kJ/mol。我们定量地评估了分子间相互作用的衰减，这是由于偶极诱导的堆积效应和空间位阻效应之间的竞争在氟碳链段的F4-DMPC。
Fluorinated lipids and surfactants are attractive biomimetic materials for the extraction and reorganization of membrane proteins because of the biological inertness of fluorocarbons. We investigated the fundamental physical properties of a partially fluorinated phospholipid (F4-DMPC), such as phase transition, area thermal expansion, and lateral lipid diffusion, to evaluate the intermolecular interaction of F4-DMPC in the hydrophobic region quantitatively on the basis of free-volume theory. Fluorescence microscope observation of the supported lipid bilayer (SLB) of F4-DMPC showed that the phase transition between the liquid crystalline and gel phases occurred at 5 °C and that the area thermal expansion coefficient was independent of the temperature near the phase transition temperature. We performed a single particle tracking of the F4-DMPC-SLB on a SiO2/Si substrate, to measure the diffusion coefficient and its temperature dependence. The apparent activation energy (E′a) of lateral lipid diffusion, which is an indicator of intermolecular interaction, was 39.1 kJ/mol for F4-DMPC, and 48.2 kJ/mol for a nonfluorinated 1,2-dioleoyl-sn-glycero-3-phosphocholine as a control. The difference of 9 kJ/mol inE′awas significant compared with the difference due to the acyl chain species among nonfluorinated phosphatidylcholine and also that caused by the addition of cholesterol and alcohol in the bilayer membranes. We quantitatively evaluated the attenuation of intermolecular interaction, which results from the competition between the dipole-induced packing effect and steric effect at the fluorocarbon segment in F4-DMPC.