Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada.
Faraday Discuss. 2010;144:393-409; discussion 445-81. doi: 10.1039/b905647e.
We have used molecular dynamics simulations with coarse-grained and atomistic models to study the lateral pressure profiles in lipid monolayers. We first consider simple oillair and oil/water interfaces, and then proceed to lipid monolayers at air/water and oil/water interfaces. The results are qualitatively similar in both atomistic and coarse-grained models. The lateral pressure profile in a monolayer is characterized by a headgroup/water pressure-interfacial tension-chain pressure pattern. In contrast to lipid bilayers, the pressure decreases towards the chain free ends. An additional chain/air tension peak is present in monolayers at the air/water interface. Lateral pressure profiles are calculated for monolayers of different lipid composition under varying surface tension. Increasing the surface tension suppresses both pressure peaks and widens the interfacial tension in monolayers at the oil/water interface, and mainly suppresses the chain pressure in monolayers at the air/water interface. In monolayers in the liquid-condensed phase, the pressure peaks split due to ordering. Variation of lipid composition leads to noticeable changes in all regions of the pressure profile at a fixed surface tension.
我们使用粗粒化和原子模型的分子动力学模拟来研究脂质单层中的侧向压力分布。我们首先考虑简单的油/气和油/水界面，然后再研究空气/水和油/水界面处的脂质单层。原子模型和粗粒化模型的结果在定性上是相似的。单层中的侧向压力分布特征是头部基团/水压力-界面张力-链压力模式。与脂质双层不同，压力朝着链自由端减小。在空气/水界面处的单层中存在额外的链/空气张力峰。我们在不同表面张力下计算了不同脂质组成的单层的侧向压力分布。增加表面张力会抑制两个压力峰并扩大油/水界面处单层的界面张力，并且主要抑制空气/水界面处单层的链压力。在处于液相凝聚相的单层中，由于有序化，压力峰会分裂。在固定表面张力下，脂质组成的变化会导致压力分布的所有区域发生明显变化。
