Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-Ku, Sendai 980-8578, Japan.
JST PRESTO, Kawaguchi, Saitama 332-0012, Japan.
J Phys Chem Lett. 2022 Jun 23;13(24):5692-5697. doi: 10.1021/acs.jpclett.2c00962. Epub 2022 Jun 16.
Liquid-liquid phase separation (LLPS) is an important phenomenon in biology, and it is desirable to develop quantitative methods to analyze protein droplets generated by LLPS. This study quantified the change in protein concentration in a droplet in label-free and single-droplet conditions using Raman imaging and the Raman band of water as an intensity standard. Small changes in the protein concentration with variations in pH and salt concentration were observed, and it was shown that the concentration in the droplet decreases as the conditions become less favorable for droplet formation. The effect of exposure to 1,6-hexanediol was also examined, and this additive was found to decrease the protein concentration in the droplet. A model can be proposed in which the addition of 1,6-hexanediol reduces the protein concentration in the droplet, and the droplet disappears when the concentration falls below a certain threshold value.
液-液相分离（LLPS）是生物学中的一个重要现象，人们期望开发定量方法来分析由 LLPS 产生的蛋白质液滴。本研究使用拉曼成像和水的拉曼带作为强度标准，在无标记和单液滴条件下定量分析了液滴中蛋白质浓度的变化。观察到 pH 值和盐浓度变化时蛋白质浓度的微小变化，并表明随着液滴形成条件变得不利，液滴中的浓度降低。还研究了暴露于 1,6-己二醇的效果，发现这种添加剂会降低液滴中的蛋白质浓度。可以提出一个模型，其中添加 1,6-己二醇会降低液滴中的蛋白质浓度，并且当浓度降至某个阈值以下时，液滴会消失。
