Stabilization of pores in lipid bilayers by anisotropic inclusions
Stabilization of pores in lipid bilayers by anisotropic inclusions
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DOI：
10.1021/jp035035a
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发表时间：
2003-11-13
影响因子：
3.3
通讯作者：
May, S
中科院分区：
文献类型：
--
作者：
Fosnaric, M;Kralj-Iglic, V;May, S
脂质双层中的孔通常是不稳定的;它们由于孔边缘的高度不利的线张力而收缩。即使在带电脂质或某些添加剂如去污剂或各向同性膜内含物的存在下，膜孔通常也不会被能量稳定化。我们提出了一个理论模型，预测在脂质膜中存在稳定的孔，诱导各向异性夹杂物的存在。我们的模型是基于一个现象学的自由能表达式，涉及三个贡献：与线张力的孔在没有夹杂物，带电膜的孔的静电能，夹杂物和宿主膜之间的相互作用能相关的能量。我们发现，最佳的孔径是由各向异性夹杂物的形状：鞍状夹杂物有利于小孔，而更多的楔形夹杂物引起较大的孔径。我们讨论了我们的模型可能的应用，并用它来解释所观察到的依赖性的孔半径在膜上的红细胞鬼周围的溶液的离子强度。
Pores in lipid bilayers are usually not stable; they shrink because of the highly unfavorable line tension of the pore rim. Even in the presence of charged lipids or certain additives such as detergents or isotropic membrane inclusions, membrane pores are generally not expected to be energetically stabilized. We present a theoretical model that predicts the existence of stable pores in a lipid membrane, induced by the presence of anisotropic inclusions. Our model is based on a phenomenological free energy expression that involves three contributions: the energy associated with the line tension of the pore in the absence of inclusions, the electrostatic energy of the pore for charged membranes, and the interaction energy between the inclusions and the host membrane. We show that the optimal pore size is governed by the shape of the anisotropic inclusions: saddle-like inclusions favor small pores, whereas more wedgelike inclusions give rise to larger pore sizes. We discuss possible applications of our model and use it to explain the observed dependency of the pore radius in the membrane of red blood cell ghosts on the ionic strength of the surrounding solution.