Molecular modeling of lipid membrane curvature induction by a peptide: more than simply shape.
Molecular modeling of lipid membrane curvature induction by a peptide: more than simply shape.
复制标题
肽诱导脂质膜曲率的分子模型：不仅仅是形状。
DOI：
10.1016/j.bpj.2014.02.037
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发表时间：
2014
影响因子：
3.4
通讯作者：
Pastor,RichardW
中科院分区：
文献类型：
--
作者：
Sodt,AlexanderJ;Pastor,RichardW
包埋在脂质双层中的两亲性螺旋的分子动力学模拟表明，它将诱导显著的正曲率（例如，直径为20 nm，表面覆盖率为16%的管）。的感应是一个连续模型预测，只考虑夹杂物的形状的两倍。解释的差异，在额外存在的特定的相互作用，仅由分子模型描述。单独的分子形状不足以定量模拟曲率的结论得到了具有大头部和小头部基团（分别为胆碱和乙醇胺）的脂质以及去除脂质尾部（模拟溶血脂质）的分子和连续模型的对比的支持。对于分子模型，曲率倾向是通过计算相对于弯曲的自由能的导数来分析的。连续介质模型预测，夹杂物将软化头基区域附近的双层，这种效果可能会削弱曲率感应。所有原子的预测是一致的，通过两亲性螺旋和结合到脂质体的自由能的变化的tuphiles的程度的实验观察。
Molecular dynamics simulations of an amphipathic helix embedded in a lipid bilayer indicate that it will induce substantial positive curvature (e.g., a tube of diameter 20 nm at 16% surface coverage). The induction is twice that of a continuum model prediction that only considers the shape of the inclusion. The discrepancy is explained in terms of the additional presence of specific interactions described only by the molecular model. The conclusion that molecular shape alone is insufficient to quantitatively model curvature is supported by contrasting molecular and continuum models of lipids with large and small headgroups (choline and ethanolamine, respectively), and of the removal of a lipid tail (modeling a lyso-lipid). For the molecular model, curvature propensity is analyzed by computing the derivative of the free energy with respect to bending. The continuum model predicts that the inclusion will soften the bilayer near the headgroup region, an effect that may weaken curvature induction. The all-atom predictions are consistent with experimental observations of the degree of tubulation by amphipathic helices and variation of the free energy of binding to liposomes.