Structural change in lipid bilayers and water penetration induced by shock waves: Molecular dynamics simulations
Structural change in lipid bilayers and water penetration induced by shock waves: Molecular dynamics simulations
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DOI：
10.1529/biophysj.105.077677
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发表时间：
2006-09-01
影响因子：
3.4
通讯作者：
Fujikawa, Shigeo
中科院分区：
文献类型：
--
作者：
Koshiyama, Kenichiro;Kodama, Tetsuya;Fujikawa, Shigeo
采用非定常非平衡分子动力学模拟方法，对激波作用下磷脂双分子层的结构变化进行了数值研究。激波的作用是由水分子的动量变化来模拟的，因此我们证明了导致双分子层的坍塌和反弹之后是水分子渗透到双分子层的疏水区域。详细分析了双层坍塌回弹过程中出现的高速现象，重点分析了双层厚度、酰基链弯曲角度、脂质分子横向流动性、水分子渗透速率的变化。结果表明，高速现象可分为两个阶段：第一阶段双层厚度和阶数参数迅速减小，第二阶段恢复相对缓慢。在第二阶段，水分子被稳定地引入疏水区。激波脉冲增强了水分子的穿透力，这与最近的实验结果在性质上是一致的。
The structural change of a phospholipid bilayer in water under the action of a shock wave is numerically studied with unsteady nonequilibrium molecular dynamics simulations. The action of shock waves is modeled by the momentum change of water molecules, and thereby we demonstrate that the resulting collapse and rebound of the bilayer are followed by the penetration of water molecules into the hydrophobic region of the bilayer. The high-speed phenomenon that occurs during the collapse and rebound of the bilayer is analyzed in detail, particularly focusing on the change of bilayer thickness, the acyl chain bend angles, the lateral fluidity of lipid molecules, and the penetration rate of water molecules. The result shows that the high-speed phenomenon can be divided into two stages: in the first stage the thickness of bilayer and the order parameter are rapidly reduced, and then in the second stage they are recovered relatively slowly. It is in the second stage that water molecules are steadily introduced into the hydrophobic region. The penetration of water molecules is enhanced by the shock wave impulse and this qualitatively agrees with a recent experimental result.