Energy of dissociation of lipid bilayer from the membrane skeleton of red blood cells
Energy of dissociation of lipid bilayer from the membrane skeleton of red blood cells
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DOI：
10.1016/s0006-3495(97)78910-0
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发表时间：
1997-06-01
影响因子：
3.4
通讯作者：
Waugh, RE
中科院分区：
文献类型：
--
作者：
Hwang, WC;Waugh, RE
脂双层和膜骨架之间的联系对细胞功能很重要。在红细胞中，这种关联的缺陷可导致各种形式的溶血性贫血。虽然参与这种关联的蛋白质已被很好地表征，但这种关联的物理强度才刚刚开始研究。从膜形成膜材料的小圆柱形链（系链）涉及脂质双层与膜骨架的分离。通过测量形成系链所需的力，并且知道由于脂质双层的变形而对力的贡献，可以计算由于膜骨架与脂质双层的分离而对系链形成的功的额外贡献。在本研究中，我们测量系绳形成过程中使用微悬臂梁（薄，灵活的玻璃纤维）作为力传感器的束缚力。进行红细胞轮廓的数值计算，以检查轮廓的形状如何影响系绳半径的计算，以及随后的每单位面积分离功W-sk和弯曲刚度k（c）。在高抽吸压力和小外力下，红细胞轮廓可以准确地建模为球体，但在低抽吸压力和大外力下，轮廓偏离球体并可能影响计算。根据能量平衡和细胞轮廓的数值计算，得到膜弯曲刚度k（c）= 2.0 × 10 ~（-19）Nm，单位面积分离功W-sk = 0.06mJ/m ~（2）。
The association between the lipid bilayer and the membrane skeleton is important to cell function. In red blood cells, defects in this association can lead to various forms of hemolytic anemia. Although proteins involved in this association have been well characterized biochemically, the physical strength of this association is only beginning to be studied. Formation of a small cylindrical strand of membrane material (tether) from the membrane involves separation of the lipid bilayer from the membrane skeleton. By measuring the force required to form a tether, and knowing the contribution to the force due to the deformation of a lipid bilayer, it is possible to calculate the additional contribution to the work of tether formation due to the separation of membrane skeleton from the lipid bilayer. In the present study, we measured the tethering force during tether formation using a microcantilever (a thin, flexible glass fiber) as a force transducer. Numerical calculations of the red cell contour were performed to examine how the shape of the contour affects the calculation of tether radius, and subsequently separation work per unit area W-sk and bending stiffness k(c). At high aspiration pressure and small external force, the red cell contour can be accurately modeled as a sphere, but at low aspiration pressure and large external force, the contour deviates from a sphere and may affect the calculation. Based on an energy balance and numerical calculations of the cell contour, values of the membrane bending stiffness k(c) = 2.0 x 10(-19) Nm and the separation work per unit area W-sk = 0.06 mJ/m(2) were obtained.