Hutchison Jaime B, Karunanayake Mudiyanselage Aruni P K K, Weis Robert M, Dinsmore Anthony D
Department of Physics, University of Massachusetts Amherst, Hasbrouck Lab 411, 666 North Pleasant Street, Amherst, MA 01003, USA.
Department of Chemistry, University of Massachusetts Amherst, USA.
Soft Matter. 2016 Feb 28;12(8):2465-72. doi: 10.1039/c5sm02496j.
The binding affinity of a curvature-sensing protein domain (N-BAR) is measured as a function of applied osmotic stress while the membrane curvature is nearly constant. Varying the osmotic stress allows us to control membrane tension, which provides a probe of the mechanism of binding. We study the N-BAR domain of the Drosophila amphiphysin and monitor its binding on 50 nm-radius vesicles composed of 90 mol% DOPC and 10 mol% PIP. We find that the bound fraction of N-BAR is enhanced by a factor of approximately 6.5 when the tension increases from zero to 2.6 mN m(-1). This tension-induced response can be explained by the hydrophobic insertion mechanism. From the data we extract a hydrophobic domain area that is consistent with known structure. These results indicate that membrane stress and strain could play a major role in the previously reported curvature-affinity of N-BAR.
在膜曲率几乎保持恒定的情况下，测量一种曲率传感蛋白结构域（N-BAR）的结合亲和力与施加的渗透压的函数关系。改变渗透压使我们能够控制膜张力，从而为结合机制提供一种探究手段。我们研究了果蝇发动蛋白的N-BAR结构域，并监测其在由90摩尔％的二油酰磷脂酰胆碱（DOPC）和10摩尔％的磷脂酰肌醇（PIP）组成的50纳米半径囊泡上的结合情况。我们发现，当张力从零增加到2.6毫牛顿/米（-1）时，N-BAR的结合比例提高了约6.5倍。这种张力诱导的响应可以用疏水插入机制来解释。从数据中我们提取出一个与已知结构相符的疏水域面积。这些结果表明，膜应力和应变可能在先前报道的N-BAR的曲率亲和力中起主要作用。
