Laboratory of Physical Chemistry, Department of Chemistry and Applied Bioscience, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland.
Institute of Biochemistry, Department of Biology, ETH Zurich, Hönggerbergring 64, 8093, Zürich, Switzerland.
Angew Chem Int Ed Engl. 2022 Oct 4;61(40):e202204311. doi: 10.1002/anie.202204311. Epub 2022 Aug 31.
Interaction of heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) with specific single-stranded RNA and its relation to liquid-liquid phase separation (LLPS) were studied in vitro by magnetic resonance based on site-directed spin labelling. An ensemble model of dispersed hnRNP A1 in the absence of RNA was derived from distance distributions between spin labelled sites and small angle X-ray scattering. This model revealed a compact state of the low-complexity domain and its interaction with the RNA recognition motifs. Paramagnetic relaxation enhancement NMR spectroscopy confirmed this interaction. Addition of RNA to dispersed hnRNP A1 induced liquid-droplet formation. Such LLPS depended on RNA concentration and sequence, with continuous wave EPR spectroscopy showing an influence of RNA point mutations on local protein dynamics. We propose that an interplay of sequence-specific RNA binding and LLPS contributes to regulation of specific RNA segregation during stress response.
hnRNP A1（异质核核糖核蛋白 A1）与特定的单链 RNA 的相互作用及其与液-液相分离（LLPS）的关系在体外通过基于磁共振的定点自旋标记进行了研究。从无 RNA 存在时的自旋标记位点之间的距离分布导出了 hnRNP A1 分散体的集合模型，并通过小角度 X 射线散射进行了验证。该模型揭示了低复杂度结构域的紧凑状态及其与 RNA 识别基序的相互作用。顺磁弛豫增强 NMR 光谱学证实了这种相互作用。向分散的 hnRNP A1 中添加 RNA 会诱导液滴形成。这种 LLPS 取决于 RNA 浓度和序列，连续波 EPR 光谱学表明 RNA 点突变会影响局部蛋白质动力学。我们提出，序列特异性 RNA 结合和 LLPS 的相互作用有助于在应激反应过程中调节特定 RNA 的分离。
