Shakya Anisha, King John T
Center for Soft and Living Matter, Institute for Basic Science, Ulsan 44919, Republic of Korea.
ACS Macro Lett. 2018 Oct 16;7(10):1220-1225. doi: 10.1021/acsmacrolett.8b00565. Epub 2018 Sep 18.
Bulk-level measurements of dynamics have suggested that phase-separated, protein-nucleic acid rich droplets can be viewed as simple liquids. In this report, we show that histone proteins spontaneously phase separate into liquid-like droplets in the presence of DNA. Using super-resolution fluorescence microscopy, we find that molecular transport in these droplets is non-Fickian (subdiffusive) at nanoscopic length scales. This observation cannot be explained by charge-charge interactions. Instead, our results strongly suggest that cation-π interactions drive the non-Fickian behavior. Given the ubiquity of cationic and aromatic moieties in protein-nucleic acid rich liquid-like phases observed in cells, we anticipate that non-Fickian diffusion is a general transport mechanism in such phases.
对动力学的整体水平测量表明，相分离的、富含蛋白质 - 核酸的液滴可被视为简单液体。在本报告中，我们表明组蛋白在DNA存在下会自发相分离成液滴状液滴。使用超分辨率荧光显微镜，我们发现在这些液滴中，纳米尺度下的分子运输是非菲克（亚扩散）的。这一观察结果无法用电荷 - 电荷相互作用来解释。相反，我们的结果强烈表明阳离子 - π相互作用驱动了这种非菲克行为。鉴于在细胞中观察到的富含蛋白质 - 核酸的类液相中普遍存在阳离子和芳香族部分，我们预计非菲克扩散是此类相中一种普遍的运输机制。
