Chou T, Jarić M V, Siggia E D
Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.
Biophys J. 1997 May;72(5):2042-55. doi: 10.1016/S0006-3495(97)78848-9.
The electrostatic contribution to spontaneous membrane curvature is calculated within Poisson-Boltzmann theory under a variety of assumptions and emphasizing parameters in the physiological range. Asymmetrical surface charges can be fixed with respect to bilayer midplane area or with respect to the lipid-water area, but induce curvatures of opposite signs. Unequal screening layers on the two sides of a vesicle (e.g., multivalent cationic proteins on one side and monovalent salt on the other) also induce bending. For reasonable parameters, tubules formed by electrostatically induced bending can have radii in the 50-100-nm range, often seen in many intracellular organelles. Thus membrane associated proteins may induce curvature and subsequent budding, without themselves being intrinsically curved. Furthermore, we derive the previously unexplored effects of respecting the strict conservation of charge within the interior of a vesicle. The electrostatic component of the bending modulus is small under most of our conditions and is left as an experimental parameter. The large parameter space of conditions is surveyed in an array of graphs.
在泊松-玻尔兹曼理论下，在各种假设条件下并着重考虑生理范围内的参数，计算了静电对自发膜曲率的贡献。不对称表面电荷可以相对于双层中平面面积固定，也可以相对于脂质-水面积固定，但会诱导出相反符号的曲率。囊泡两侧不等的屏蔽层（例如，一侧为多价阳离子蛋白而另一侧为单价盐）也会诱导弯曲。对于合理的参数，由静电诱导弯曲形成的微管半径可在50 - 100纳米范围内，这在许多细胞内细胞器中经常可见。因此，膜相关蛋白可能诱导曲率并随后出芽，而其本身并非固有弯曲。此外，我们推导了在囊泡内部严格遵守电荷守恒的先前未探索的效应。在我们的大多数条件下，弯曲模量的静电分量很小，并留作实验参数。通过一系列图表研究了条件的大参数空间。
