Akimov Sergey A, Kuzmin Peter I, Zimmerberg Joshua, Cohen Fredric S
Laboratory of Bioelectrochemistry, Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia 119991.
Phys Rev E Stat Nonlin Soft Matter Phys. 2007 Jan;75(1 Pt 1):011919. doi: 10.1103/PhysRevE.75.011919. Epub 2007 Jan 18.
The effect of an external applied lateral tension on the line tension between two domains of different thickness in a lipid bilayer membrane is calculated. The thick domain is treated as a liquid-ordered phase in order to model a raft in a biological membrane; the thin domain is considered a liquid-disordered phase to model the surrounding region. In our model, the monolayers elastically distort at the boundary to create a smooth rather than steplike boundary to avoid exposure of the hydrophobic interior of the thick raft to water. The energy of this distortion is described by the fundamental deformations of splay and tilt. This energy per unit length of boundary yields the line tension of the raft. Applying lateral tension alters the fundamental deformations such that line tension increases. This increase in line tension is larger when the spontaneous curvature of a raft is greater than that of the surround; if the spontaneous curvature of the raft is less than that of the surround, the increase of the line tension due to application of the lateral tension is more modest.
计算了外部施加的横向张力对脂质双层膜中不同厚度的两个区域之间线张力的影响。厚区域被视为液态有序相，以模拟生物膜中的筏；薄区域被认为是液态无序相，以模拟周围区域。在我们的模型中，单分子层在边界处弹性变形以形成平滑而非阶梯状的边界，以避免厚筏的疏水内部暴露于水中。这种变形的能量由展曲和倾斜的基本变形来描述。边界每单位长度的这种能量产生筏的线张力。施加横向张力会改变基本变形，从而使线张力增加。当筏的自发曲率大于周围环境的自发曲率时，线张力的这种增加更大；如果筏的自发曲率小于周围环境的自发曲率，则由于施加横向张力而导致的线张力增加更为适度。
