Latham Andrew P, Zhu Longchen, Sharon Dina A, Ye Songtao, Willard Adam P, Zhang Xin, Zhang Bin
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, United States.
Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, China.
Elife. 2025 Mar 26;12:RP90750. doi: 10.7554/eLife.90750.
The phase separation of intrinsically disordered proteins is emerging as an important mechanism for cellular organization. However, efforts to connect protein sequences to the physical properties of condensates, that is, the molecular grammar, are hampered by a lack of effective approaches for probing high-resolution structural details. Using a combination of multiscale simulations and fluorescence lifetime imaging microscopy experiments, we systematically explored a series of systems consisting of diblock elastin-like polypeptides (ELPs). The simulations succeeded in reproducing the variation of condensate stability upon amino acid substitution and revealed different microenvironments within a single condensate, which we verified with environmentally sensitive fluorophores. The interspersion of hydrophilic and hydrophobic residues and a lack of secondary structure formation result in an interfacial environment, which explains both the strong correlation between ELP condensate stability and interfacial hydrophobicity scales, as well as the prevalence of protein-water hydrogen bonds. Our study uncovers new mechanisms for condensate stability and organization that may be broadly applicable.
内在无序蛋白质的相分离正成为细胞组织的一种重要机制。然而，由于缺乏探测高分辨率结构细节的有效方法，将蛋白质序列与凝聚物的物理性质（即分子语法）联系起来的努力受到了阻碍。通过结合多尺度模拟和荧光寿命成像显微镜实验，我们系统地探索了一系列由双嵌段弹性蛋白样多肽（ELP）组成的体系。模拟成功地再现了氨基酸取代后凝聚物稳定性的变化，并揭示了单个凝聚物内不同的微环境，我们用对环境敏感的荧光团对此进行了验证。亲水性和疏水性残基的散布以及二级结构形成的缺乏导致了一种界面环境，这既解释了ELP凝聚物稳定性与界面疏水性尺度之间的强相关性，也解释了蛋白质-水氢键的普遍存在。我们的研究揭示了可能广泛适用的凝聚物稳定性和组织的新机制。
