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_p, suggesting a mechanism dependent on the hydrophobic effect.

中文翻译：

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甲基-β-环糊精诱导的脂质囊泡增溶的热力学：脂质头基和骨干的影响。

磷脂的低水溶性使其在研究脂质运输和新陈代谢到工程化具有脂质横向不对称性的模型膜的研究中必须使用脂质载体。已被证明特别有用的一种特定脂质载体是甲基-β-环糊精（MβCD）。为了评估MβCD与结构上不同的磷脂的相互作用，本工作报告了等温滴定量热法与动态光散射测量相结合的结果。结果表明，MβCD与由单一类型的脂质组成的大单层囊泡的相互作用导致脂质囊泡的增溶，并因此使MβCD与脂质复合。这种相互作用取决于脂质头基的性质，与磷脂酰胆碱相比，与磷脂酰甘油的相互作用更好。也有可能显示磷脂主链在这种相互作用中所起的作用。在许多情况下，可以从双层中提取脂质所需的能量来定性地解释从双层到结合环糊精的状态下，一种脂质与另一种脂质之间转移能量的差异。在所有情况下，数据表明，囊泡的溶解是由负的大Δ熵驱动的 定性地解释了从双层中提取脂质所需的能量，可以定性地解释一种脂质和另一种脂质从双层到结合环糊精的状态之间传递能量的差异。在所有情况下，数据表明，囊泡的溶解是由负的大Δ熵驱动的 定性地解释了从双层中提取脂质所需的能量，可以定性地解释一种脂质和另一种脂质从双层到结合环糊精的状态之间传递能量的差异。在所有情况下，数据表明，囊泡的溶解是由负的大Δ熵驱动的C _p，表明机制取决于疏水作用。