Zoni Valeria, Campomanes Pablo, Vanni Stefano
Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.
Soft Matter. 2021 Jun 2;17(21):5329-5335. doi: 10.1039/d0sm02270e.
In vitro reconstitutions of lipid membranes have proven to be an indispensable tool to rationalize their molecular complexity and to understand their role in countless cellular processes. However, amongst the various techniques used to reconstitute lipid bilayers in vitro, several approaches are not solvent-free, but rather contain residual hydrophobic solvents in between the two bilayer leaflets, generally as a consequence of the procedure used to generate the bilayer. To what extent the presence of these hydrophobic solvents modifies bilayer properties with respect to native, solvent-free, conditions remains an open question that has important implications for the appropriate interpretation of numerous experimental observations. Here, we thorouhgly characterize hydrophobic solvent-rich lipid bilayers using atomistic molecular dynamics simulations. Our data indicate that while the presence of hydrophobic solvents at high concentrations, such as hexadecane, has a significant effect on membrane thickness, their effects on surface properties, membrane order and lateral stress are quite moderate. Our results corroborate the validity of in vitro approaches as model systems for the investigations of biological membranes but raise a few cautionary aspects that must be considered when investigating specific membrane properties.
脂质膜的体外重构已被证明是一种不可或缺的工具，可用于阐明其分子复杂性，并理解其在无数细胞过程中的作用。然而，在用于体外重构脂质双层的各种技术中，有几种方法并非无溶剂，而是在两个双层小叶之间含有残留的疏水溶剂，这通常是生成双层所使用的程序导致的。相对于天然的无溶剂条件，这些疏水溶剂的存在在多大程度上改变了双层性质，仍然是一个悬而未决的问题，这对于正确解释大量实验观察结果具有重要意义。在这里，我们使用原子分子动力学模拟全面表征了富含疏水溶剂的脂质双层。我们的数据表明，虽然高浓度疏水溶剂（如十六烷）的存在对膜厚度有显著影响，但其对表面性质、膜有序性和侧向应力的影响相当温和。我们的结果证实了体外方法作为生物膜研究模型系统的有效性，但也提出了一些在研究特定膜性质时必须考虑的警示因素。
