Department of Biochemistry and Biomedical Sciences, McMaster University, Health Sciences Centre , Hamilton, Ontario L8S 4K1 Canada.
Langmuir. 2017 Dec 5;33(48):13882-13891. doi: 10.1021/acs.langmuir.7b03447. Epub 2017 Nov 21.
The low aqueous solubility of phospholipids makes necessary the use of lipid carriers in studies ranging from lipid traffic and metabolism to the engineering of model membranes bearing lipid transverse asymmetry. One particular lipid carrier that has proven to be particularly useful is methyl-β-cyclodextrin (MβCD). To assess the interaction of MβCD with structurally different phospholipids, the present work reports the results of isothermal titration calorimetry in conjunction with dynamic light scattering measurements. The results showed that the interaction of MβCD with large unilamellar vesicles composed of a single type of lipid led to the solubilization of the lipid vesicle and, consequently, the complexation of MβCD with the lipids. This interaction is dependent on the nature of the lipid headgroup, with a preferable interaction with phosphatidylglycerol in comparison to phosphatidylcholine. It was also possible to show a role played by the phospholipid backbone in this interaction. In many cases, the differences in the transfer energy between one lipid and another in going from a bilayer to a cyclodextrin-bound state can be qualitatively explained by the energy required to extract the lipid from a bilayer. In all cases, the data showed that the solubilization of the vesicles is entropically driven with a large negative ΔC, suggesting a mechanism dependent on the hydrophobic effect.
由于磷脂的水溶性较低，在从脂质运输和代谢到具有脂质横向不对称的模型膜工程等研究中，必须使用脂质载体。已证明甲基-β-环糊精（MβCD）是一种特别有用的脂质载体。为了评估 MβCD 与结构不同的磷脂的相互作用，本工作报告了结合动态光散射测量的等温滴定量热法的结果。结果表明，MβCD 与由单一类型脂质组成的大单室囊泡的相互作用导致脂质囊泡的溶解，并且 MβCD 与脂质的复合。这种相互作用取决于脂质头部基团的性质，与磷脂酰胆碱相比，与磷脂酰甘油的相互作用更好。还可以证明在这种相互作用中磷脂骨架的作用。在许多情况下，可以通过从双层到环糊精结合状态提取脂质所需的能量定性地解释从一种脂质到另一种脂质的转移能量之间的差异。在所有情况下，数据表明囊泡的溶解是由熵驱动的，具有很大的负 ΔC，表明这是一种依赖于疏水作用的机制。
