Yang Alexander, Moore Timothy C, Iacovella Christopher R, Thompson Michael, Moore David J, McCabe Clare
Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37212, United States.
Multiscale Modeling and Simulation Center, Vanderbilt University, Nashville, Tennessee 37212, United States.
J Phys Chem B. 2020 Apr 16;124(15):3043-3053. doi: 10.1021/acs.jpcb.0c00490. Epub 2020 Apr 7.
The structural properties of two- and three-component gel-phase bilayers were studied using molecular dynamics simulations. The bilayers contain distearoylphosphatidylcholine (DSPC) phospholipids mixed with alcohols and/or fatty acids of varying tail lengths, with carbon chain lengths of 12, 16, and 24 studied. Changes in both headgroup chemistry and tail length are found to affect the balance between steric repulsion and van der Waals attraction within the bilayers, manifesting in different bilayer structural properties. Lipid components are found to be located at different depths within the bilayer depending on both chain length and headgroup chemistry. The highest bilayer ordering and lowest area per tail are found in systems with medium-length tails. While longer tails can enhance van der Waals attractions, the increased tail-length asymmetry is found to induce disorder and reduce tail packing. Bulkier headgroups further increase steric repulsion, as reflected in increased component offsets and reduced tail packing. These findings help explain how bilayer composition affects the structure of gel-phase bilayers.
利用分子动力学模拟研究了二元和三元凝胶相双层膜的结构特性。双层膜包含与不同尾长的醇和/或脂肪酸混合的二硬脂酰磷脂酰胆碱（DSPC）磷脂，研究了碳链长度为12、16和24的情况。发现头基化学性质和尾长的变化都会影响双层膜内空间排斥和范德华吸引力之间的平衡，表现为不同的双层膜结构特性。发现脂质成分根据链长和头基化学性质位于双层膜内的不同深度。在具有中等长度尾巴的体系中发现了最高的双层膜有序性和每条尾巴最低的面积。虽然较长的尾巴可以增强范德华吸引力，但发现增加的尾巴长度不对称性会导致无序并减少尾巴堆积。体积较大的头基进一步增加了空间排斥，这反映在成分偏移增加和尾巴堆积减少上。这些发现有助于解释双层膜组成如何影响凝胶相双层膜的结构。
