Department of Physics, Ochanomizu University, Bunkyo, Tokyo, Japan.
Biophys J. 2010 Jul 21;99(2):472-9. doi: 10.1016/j.bpj.2010.03.064.
We have investigated shape deformations of binary giant unilamellar vesicles (GUVs) composed of cone- and cylinder-shaped lipids. By coupling the spontaneous curvature of lipids with the phase separation, we demonstrated pore opening and closing in GUVs. When the temperature was set below the chain melting transition temperature of the cylinder-shaped lipid, the GUVs burst and then formed a single large pore, where the cone shape lipids form a cap at the edge of the bilayer to stabilize the pore. The pore closed when we increased the temperature above the transition temperature. The pore showed three types of shapes depending on the cone-shaped lipid concentration: simple circular, rolled-rim, and wrinkled-rim pores. These pore shape changes indicate that the distribution of the cone- and cylinder-shaped lipids is asymmetric between the inner and outer leaflets in the bilayer. We have proposed a theoretical model for a two-component membrane with an edge of bilayer where lipids can transfer between two leaflets. Using this model, we have reproduced numerically the observed shape deformations at the rim of pore.
我们研究了由锥形和圆柱形脂质组成的二元巨单层囊泡(GUV)的形状变形。通过将脂质的自发曲率与相分离耦合,我们在 GUV 中演示了孔的开启和关闭。当温度设置在圆柱形脂质的链熔融转变温度以下时,GUV 会破裂,然后形成一个大孔,其中锥形脂质在双层边缘形成一个帽来稳定孔。当温度升高到转变温度以上时,孔会关闭。根据锥形脂质的浓度,孔呈现出三种形状:简单的圆形、卷边和波纹边孔。这些孔形状的变化表明,在双层的内外叶之间,锥形和圆柱形脂质的分布是不对称的。我们提出了一个具有双层边缘的双组分膜的理论模型,其中脂质可以在两个叶层之间转移。使用这个模型,我们数值再现了观察到的孔边缘的形状变形。