A molecular dynamics study of DMPC lipid bilayers interacting with dimethylsulfoxide-water mixtures.
A molecular dynamics study of DMPC lipid bilayers interacting with dimethylsulfoxide-water mixtures.
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DMPC 脂质双层与二甲基亚砜-水混合物相互作用的分子动力学研究。
DOI：
10.1007/s00232-012-9483-x
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Devireddy,RV
中科院分区：
文献类型：
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作者：
Pinisetty,D;Alapati,R;Devireddy,RV
用分子动力学方法研究了二甲基亚砜（DMSO）在两性离子型二肉豆蔻酰磷脂酰胆碱（DMPC）脂双层中的扩散过程。为了解释细胞内部和外部之间的冷冻保护剂浓度差异，模拟了将具有和不具有DMSO的两个水性储器分开的双DMPC脂质双层。模拟模型的初始配置中，DMSO分子以约3和约6 mol%的两种不同浓度存在于其中一个水相中（细胞外）。在323 K和1 bar下对系统进行了50 ns的MD模拟。尽管在研究中考虑的模拟时间不足以使DMSO分子达到另一水相和平衡，但扩散过程的早期阶段表明DMSO分子有向另一水相扩散的趋势。研究了在扩散过程中DMSO对双层膜结构特性的影响。模拟进行了分析，以关联的两种不同的水相的存在下，脂质双层的以下属性：面积每脂质，脂质厚度，质量密度分布，脂质尾序参数和水偶极子取向。与不含DMSO的纯DMPC双层的每种脂质的面积相比，面向DMSO-水混合物水溶液的小叶的每种脂质的面积未显示出任何显著差异。质量密度曲线显示，DMSO分子有很强的倾向，扩散到纯水的水相。针对面向DMSO-水混合物的瓣叶的sn-1尾计算的脂质尾序参数表明，与暴露于纯水的瓣叶相比，脂质尾序降低。然而，在其中单个双层通过含水DMSO-水混合物水合的系统中，脂质尾的排序要低得多。
The diffusion process of dimethylsulfoxide (DMSO) through zwitterionic dimyristoylphosphatidylcholine (DMPC) lipid bilayer was studied by means of molecular dynamics (MD) simulations. To account for the cryoprotectant concentration difference between the inside and the outside of the cell, dual DMPC lipid bilayers which separate two aqueous reservoirs with and without DMSO were modeled. The initial configuration of the simulation model had DMSO molecules present in one of the aqueous phases (outside the cell) at two different concentrations of ~3 and ~6 mol%. MD simulations were performed on the systems for 50 ns at 323 K and 1 bar. Although the simulation time considered in the study was insufficient for the DMSO molecules to reach the other aqueous phase and equilibrium, early stages of the diffusion process indicated that DMSO molecules had a tendency to diffuse towards the other aqueous phase. The effects of DMSO on bilayer structural characteristics during the diffusion process were investigated. Simulations were analyzed to correlate the following properties of lipid bilayers in the presence of two different aqueous phases: area per lipid, lipid thickness, mass density profiles, lipid tail order parameter and water dipole orientation. Area per lipid calculated for the leaflet facing the aqueous DMSO–water mixture did not show any significant difference compared to area per lipid for the DMSO-free pure DMPC bilayer. Mass density profiles revealed that DMSO molecules had a strong tendency to diffuse toward the aqueous phase with pure water. The lipid tail order parameter calculated for the sn-1 tail of the leaflet facing the aqueous DMSO–water mixture showed that the ordering of lipid tails decreased compared to the leaflet exposed to pure water. However, the ordering of lipid tails in a system where a single bilayer is hydrated by an aqueous DMSO–water mixture is far lower.