Yang Kai, Ma Yu-Qiang
National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China.
J Phys Chem B. 2009 Jan 29;113(4):1048-57. doi: 10.1021/jp805551s.
Fission is an important biological phenomenon to maintain normal functions of cells, but its mechanism is not quite clear. In this paper, the fission behaviors of a two-component lipid vesicle induced by external amphipathic inclusions are studied by the dissipative particle dynamics method. We find that the fission of the lipid domain the in a spherical vesicle will occur only when the concentration of amphipathic inclusions is beyond a threshold concentration. It reveals that this kind of fission is induced by the combination of the domain's line tension and the asymmetric distribution of the amphipathic inclusions in the membrane's inner and outer leaflets. Furthermore, we also find that the fission behaviors are influenced by the area-to-volume ratio of vesicles and the structure characters of amphipathic inclusions (e.g., chain length and rigidity). Especially, the chain length and rigidity of amphipathic inclusions have complicated effects on the vesicle fission. With the variation of these factors, the fission process will be accelerated or delayed. The present study is helpful to understand the possible fission mechanism of lipid bilayers with embedded proteins.
裂变是维持细胞正常功能的重要生物学现象，但其机制尚不完全清楚。本文采用耗散粒子动力学方法研究了外部两亲性内含物诱导的双组分脂质囊泡的裂变行为。我们发现，只有当两亲性内含物的浓度超过阈值浓度时，球形囊泡中脂质域才会发生裂变。这表明这种裂变是由域的线张力和两亲性内含物在膜内外小叶中的不对称分布共同诱导的。此外，我们还发现裂变行为受囊泡的面积与体积比以及两亲性内含物的结构特征（如链长和刚性）影响。特别是，两亲性内含物的链长和刚性对囊泡裂变有复杂的影响。随着这些因素的变化，裂变过程将加速或延迟。本研究有助于理解嵌入蛋白质的脂质双层可能的裂变机制。
