School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430074, China.
Chem Commun (Camb). 2020 Mar 12;56(21):3147-3150. doi: 10.1039/c9cc10079b.
Amyloid fibrils, implicated in health and diseases, commonly exhibit a periodic twist trait relevant to the structures and dynamics of the fibrils. However, the origins and modulations of fibril twist in complex in vivo environments are not yet fully understood. Here we highlight an important factor that causes twist variations in amyloid fibril structures-the presence of surrounding surfaces. Using cholesterol-containing lipid bilayers with varying cholesterol contents, we have demonstrated via atomic force microscopy that amyloid-β peptide fibrils initiated on membranes increase their average pitch size of twisting periodicity as the cholesterol content increases. These surface-induced twist variations arise from the enhanced hydrophobic interactions between the fibril and the surface distorting the torsional elastic energy of the fibril twisting as supported by a theory of an elastic model. These findings not only provide an important insight into fibril polymorphism phenomena resulting from the surface effects but also suggest a novel solution to modulate filament twisting on the nanoscale for biomaterials applications involving nanoscale features.
淀粉样纤维在健康和疾病中都有涉及，通常表现出与纤维结构和动力学相关的周期性扭曲特征。然而，在复杂的体内环境中，纤维扭曲的起源和调节还不完全清楚。在这里，我们强调了一个导致淀粉样纤维结构中扭曲变化的重要因素——周围表面的存在。我们使用含有不同胆固醇含量的含有胆固醇的脂质双层，通过原子力显微镜证明，在膜上起始的淀粉样β肽纤维随着胆固醇含量的增加而增加其扭转周期性的平均螺距大小。这些由表面引起的扭曲变化源于纤维与表面之间增强的疏水相互作用，扭曲弹性纤维的扭转扭转弹性的扭转弹性能量的扭曲弹性能量，这得到了弹性模型理论的支持。这些发现不仅为纤维多态性现象提供了重要的见解，这些现象是由表面效应引起的，而且还为涉及纳米级特征的生物材料应用中在纳米尺度上调节细丝扭曲提供了一种新的解决方案。
