Lipid-based mechanisms for vesicle fission.
Lipid-based mechanisms for vesicle fission.
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DOI：
10.1021/jp068277u
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发表时间：
2007-04
期刊：
影响因子：
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通讯作者：
A. J. Markvoort;A. F. Smeijers;K. Pieterse;R. V. Santen;Paj Peter Hilbers
中科院分区：
文献类型：
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作者：
A. J. Markvoort;A. F. Smeijers;K. Pieterse;R. V. Santen;Paj Peter Hilbers
脂质囊泡的形状变化和拓扑结构变化，如融合、出芽和分裂等，具有重要的化学物理和生物学意义。本文研究了脂质囊泡的分裂过程。两种不同的路线被认为是基于膜内的脂质分布的不对称性。这种不对称性由两种类型的脂质的不均匀分布组成。在第一种机制中，两种类型的脂质均匀分布在膜的两个小叶上。然而，两个小叶内的脂质的相分离导致筏的形成，筏形成可以分裂的芽。在第二种机制中，不对称性由膜的两个单层之间的组成差异组成。这种成分上的差异产生了自发的弯曲，将囊泡重塑成哑铃状，使其可以分裂。这两种途径进行了研究与分子动力学模拟使用粗粒脂质模型。对于每一个途径，获得完整的裂变所需的条件进行了研究，它表明，对于第二种途径，脂质之间的差异要小得多，需要获得裂变比第一种途径。此外，所得分裂囊泡的脂质组成显示对于两种途径是完全不同的，并且裂变途径和逆过程的途径之间存在本质差异，即，融合，是存在的。
Shape transformations and topological changes of lipid vesicles, such as fusion, budding, and fission, have important chemical physical and biological significance. In this paper, we study the fission process of lipid vesicles. Two distinct routes are considered that are both based on an asymmetry of the lipid distribution within the membrane. This asymmetry consists of a nonuniform distribution of two types of lipids. In the first mechanism, the two types of lipids are equally distributed over both leaflets of the membrane. Phase separation of the lipids within both leaflets, however, results in the formation of rafts, which form buds that can split off. In the second mechanism, the asymmetry consists of a difference in composition between the two monolayers of the membrane. This difference in composition yields a spontaneous curvature, reshaping the vesicle into a dumbbell such that it can split. Both pathways are studied with molecular dynamics simulations using a coarse-grained lipid model. For each of the pathways, the conditions required to obtain complete fission are investigated, and it is shown that for the second pathway, much smaller differences between the lipids are needed to obtain fission than for the first pathway. Furthermore, the lipid composition of the resulting split vesicles is shown to be completely different for both pathways, and essential differences between the fission pathway and the pathway of the inverse process, i.e., fusion, are shown to exist.