A molecular-dynamics study of lipid bilayers: Effects of the hydrocarbon chain length on permeability
A molecular-dynamics study of lipid bilayers: Effects of the hydrocarbon chain length on permeability
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DOI：
10.1063/1.2102900
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发表时间：
2005-11-08
影响因子：
4.4
通讯作者：
Matsumoto, Y
中科院分区：
文献类型：
--
作者：
Sugii, T;Takagi, S;Matsumoto, Y
在本文中，我们研究了脂质分子的烃链长度对小分子通过脂质双层渗透过程的影响。我们使用三种不同链长的脂质分子进行分子动力学模拟：二月桂酰磷脂酰胆碱、二肉豆蔻酰磷脂酰胆碱和二棕榈酰磷脂酰胆碱。采用空腔插入Widom法和概率比法计算了O-2、CO、NO和水分子的自由能分布。我们发现，具有较长链的脂质膜具有更大和更宽的能垒。还通过力自相关函数法和速度自相关函数法计算了水穿过双层的局部扩散系数。双层中的局部扩散系数不会因链长而显着改变。我们根据溶解度扩散模型估算了水穿过三种膜的渗透系数；我们发现水渗透性随着脂质分子链长度的增加而适度降低。
In this paper, we investigate the effects of the hydrocarbon chain length of lipid molecules on the permeation process of small molecules through lipid bilayers. We perform molecular-dynamics simulations using three kinds of lipid molecules with different chain length: dilauroylphosphatidylcholine, dimyristoylphosphatidylcholine, and dipalmiltoylphosphatidylcholine. Free-energy profiles of O-2, CO, NO, and water molecules are calculated by means of the cavity insertion Widom method and the probability ratio method. We show that the lipid membrane with longer chains has a larger and wider energy barrier. The local diffusion coefficients of water across the bilayers are also calculated by the force autocorrelation function method and the velocity autocorrelation function method. The local diffusion coefficients in the bilayers are not altered significantly by the chain length. We estimate the permeability coefficients of water across the three membranes according to the solubility-diffusion model; we find that the water permeability decreases modestly with increasing chain length of the lipid molecules.