Aix Marseille Université, CNRS, Ecole Centrale Marseille, Institut Fresnel, 13013 Marseille, France.
J Phys Chem B. 2013 Jan 24;117(3):784-8. doi: 10.1021/jp309528f. Epub 2013 Jan 14.
Amyloid fibrils are protein misfolding structures that involve a β-sheet structure and are associated with the pathologies of various neurodegenerative diseases. Here we show that Thioflavine-T and Congo Red, two major dyes used to image fibrils by fluorescence assays, can provide deep structural information when probed by means of polarization-resolved fluorescence microscopy. Unlike fluorescence anisotropy or fluorescence detected linear dichroism imaging, this technique allows to retrieve simultaneously both mean orientation and orientation dispersion of the dye, used here as a reporter of the fibril structure. We have observed that insulin amyloid fibrils exhibit a homogeneous behavior over the fibrils' length, confirming their structural uniformity. In addition, these results reveal the existence of various structures among the observed fibrils' population, in spite of a similar aspect when imaged with conventional fluorescence microscopy. This optical nondestructive technique opens perspectives for in vivo structural analyses or high throughput screening.
淀粉样纤维是涉及β-折叠结构的蛋白质错误折叠结构，与各种神经退行性疾病的病理学有关。在这里，我们表明，噻唑黄素-T 和刚果红这两种用于通过荧光分析来成像纤维的主要染料，当用偏振分辨荧光显微镜探测时，可以提供深入的结构信息。与荧光各向异性或荧光检测线二色性成像不同，该技术可以同时检索染料的平均取向和取向分散，这里将其用作纤维结构的报告器。我们观察到胰岛素淀粉样纤维在纤维长度上表现出均匀的行为，证实了它们的结构均匀性。此外，尽管用常规荧光显微镜成像时具有相似的外观，但这些结果揭示了观察到的纤维群体中存在各种结构。这种光学非破坏性技术为体内结构分析或高通量筛选开辟了前景。
