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Abstract：
Mutual interactions between components of biological membranes are pivotal for maintaining their proper biophysical properties, such as stability, fluidity, or permeability. The main building blocks of biomembranes are lipids, among which the most important are phospholipids (mainly phosphatidylcholines (PCs)) and sterols (mainly cholesterol). Although there is a plethora of reports on interactions between PCs, as well as between PCs and cholesterol, their molecular mechanism has not yet been fully explained. Therefore, to resolve this issue, we carried out systematic investigations based on the classical Langmuir monolayer technique complemented with molecular dynamics simulations. The studies involved systems containing 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) analogues possessing in the structure one or two polar functional groups similar to those of DPPC. The interactions and rheological properties of binary mixtures of DPPC analogues with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and cholesterol were compared with reference systems (DPPC/POPC and DPPC/cholesterol). This pointed to the importance of the ternary amine group in PC/cholesterol interactions, while in PC mixtures, the phosphate group played a key role. In both cases, the esterified glycerol group had an effect on the magnitude of interactions. The obtained results are crucial for establishing structure-property relationships as well as for designing substitutes for natural lipids.
摘要：
生物膜成分之间的相互作用对于保持其适当的生物物理特性至关重要，比如稳定性，流动性,或渗透性。生物膜的主要组成部分是脂质，其中最重要的是磷脂（主要是磷脂酰胆碱（PC））和甾醇（主要是胆固醇）。尽管关于PC之间的交互的报告过多，以及PC和胆固醇之间，其分子机制尚未完全解释。因此,为了解决这个问题，我们基于经典的Langmuir单层技术进行了系统的研究，并辅以分子动力学模拟。研究涉及含有1,2-二棕榈酰基-sn-甘油基-3-磷酸胆碱（DPPC）类似物的系统，其结构具有一个或两个与DPPC相似的极性官能团。将DPPC类似物与1-棕榈酰-2-油酰基-sn-甘油-3-磷酸胆碱（POPC）和胆固醇的二元混合物的相互作用和流变特性与参考系统（DPPC/POPC和DPPC/胆固醇）进行了比较。这表明三元胺基团在PC/胆固醇相互作用中的重要性，而在PC混合物中，磷酸基团起了关键作用。在这两种情况下，酯化甘油基团对相互作用的大小有影响。获得的结果对于建立结构-性质关系以及设计天然脂质的替代品至关重要。
