Effect of membrane tension on the physical properties of DOPC lipid bilayer membrane.
Effect of membrane tension on the physical properties of DOPC lipid bilayer membrane.
复制标题
DOI：
10.1016/j.bbamem.2012.05.006
复制
发表时间：
2012-09
期刊：
影响因子：
--
通讯作者：
Chachisvilis M
中科院分区：
文献类型：
--
作者：
Reddy AS;Warshaviak DT;Chachisvilis M
用分子动力学模拟方法研究了二油酰磷胆碱(DOPC)脂双层的机械敏感性。计算了在0~15dyn/cm的膜张力范围内双层膜性质的变化，如每脂的面积、体积、厚度、水化深度(HD)、水化厚度(HT)、侧向扩散系数以及脂质结构有序性的变化。结果表明，随着膜张力的增加，∼和∼的双层厚度和HD分别降低5%和5.7%，而单位脂面积、体积和HT/HD分别增加6.8%、2.4%和5%。用取向(S2)和氚(SCD)序参数表征了脂类构象和取向的变化。随着膜张力的增加，两个有序参数都表明脂质无序度增加了10-20%，主要是在疏水链的末端区域。在惯性运动、异常扩散和正常扩散三种不同的时间尺度上，分析了膜张力对DOPC双层膜中脂质横向扩散的影响。结果表明，由于等待时间的非指数分布，脂质分子的横向扩散本质上是反常的。当膜张力从0增加到15dyn/cm时，反常扩散系数和正常扩散系数分别增加了20%和52%。总之，我们的研究表明，膜张力导致膜的每脂面积、体积、极性、膜厚度和流动性发生相对显著的变化，这表明膜的机械扰动可以触发细胞中的机械敏感反应的多种机制。
Molecular dynamics simulations of a dioleoylphosphocholine (DOPC) lipid bilayer were performed to explore its mechanosensitivity. Variations in the bilayer properties, such as area per lipid, volume, thickness, hydration depth (HD), hydration thickness (HT), lateral diffusion coefficient, and changes in lipid structural order were computed in the membrane tension range 0 to 15 dyn/cm. We determined that an increase in membrane tension results in a decrease in the bilayer thickness and HD of ∼5% and ∼5.7% respectively, whereas area per lipid, volume, and HT/HD increased by 6.8%, 2.4%, and 5% respectively. The changes in lipid conformation and orientation were characterized using orientational (S2) and deuterium (SCD) order parameters. Upon increase of membrane tension both order parameters indicated an increase in lipid disorder by 10– 20%, mostly in the tail end region of the hydrophobic chains. The effect of membrane tension on lipid lateral diffusion in the DOPC bilayer was analyzed on three different time scales corresponding to inertial motion, anomalous diffusion and normal diffusion. The results showed that lateral diffusion of lipid molecules is anomalous in nature due to the non-exponential distribution of waiting times. The anomalous and normal diffusion coefficients increased by 20% and 52% when the membrane tension changed from 0 to 15 dyn/cm, respectively. In conclusion, our studies showed that membrane tension causes relatively significant changes in the area per lipid, volume, polarity, membrane thickness, and fluidity of the membrane suggesting multiple mechanisms by which mechanical perturbation of the membrane could trigger mechanosensitive response in cells.