While eukaryotic cells have a myriad of membrane-bound organelles enabling the isolation of different chemical environments, prokaryotic cells lack these defined reaction vessels. Biomolecular condensates—organelles that lack a membrane—provide a strategy for cellular organization without a physical barrier while allowing for the dynamic, responsive organization of the cell. It is well established that intrinsically disordered protein domains drive condensate formation via liquid–liquid phase separation; however, the role of globular protein domains on intracellular phase separation remains poorly understood. We hypothesized that the overall charge of globular proteins would dictate the formation and concentration of condensates and systematically probed this hypothesis with supercharged proteins and nucleic acids in E. coli. Within this study, we demonstrated that condensates form via electrostatic interactions between engineered proteins and RNA and that these condensates are dynamic and only enrich specific nucleic acid and protein components. Herein, we propose a simple model for the phase separation based on protein charge that can be used to predict intracellular condensate formation. With these guidelines, we have paved the way to designer functional synthetic membraneless organelles with tunable control over globular protein function.

中文翻译：

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通过调节蛋白质静电学在细菌中形成生物分子冷凝物

真核细胞具有无数的膜结合细胞器，能够分离不同的化学环境，而原核细胞则缺少这些明确的反应容器。生物分子缩合物（缺乏膜的细胞器）为细胞的组织提供了一种没有物理屏障的策略，同时允许细胞的动态，响应性组织。公认的是，本质上无序的蛋白质结构域通过液相分离来驱动冷凝物的形成。然而，球形蛋白结构域在细胞内相分离中的作用仍然知之甚少。我们假设球状蛋白质的总电荷将决定冷凝物的形成和浓度，并用超荷电的蛋白质和核酸系统地探讨了这一假设。大肠杆菌。在这项研究中，我们证明了缩合物是通过工程蛋白和RNA之间的静电相互作用形成的，并且这些缩合物是动态的，仅富集特定的核酸和蛋白质成分。在这里，我们提出了一个简单的基于蛋白质电荷的相分离模型，该模型可用于预测细胞内冷凝物的形成。通过这些指导，我们为设计功能性合成无膜细胞器铺平了道路，这些细胞器可通过球蛋白功能的可调控制。