The effect of polymer length in liquid-liquid phase separation
The effect of polymer length in liquid-liquid phase separation
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DOI：
10.1016/j.xcrp.2023.101415
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发表时间：
2023-05
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影响因子：
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通讯作者：
Gilberto Valdés-García;Kasun Gamage;Casey R. Smith;K. Martirosova;M. Feig;Lisa J. Lapidus
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文献类型：
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作者：
Gilberto Valdés-García;Kasun Gamage;Casey R. Smith;K. Martirosova;M. Feig;Lisa J. Lapidus
考虑到许多不同的生物分子系统正在经历这种现象，理解驱动液-液相分离（LLPS）的热力学是非常重要的。许多研究都集中在长聚合物的凝聚体上，但对短聚合物凝聚体的观察和研究很少。在这里，我们研究了由不同长度的聚腺嘌呤RNA和由RGRGG序列重复形成的肽组成的短聚合物系统，以了解LLPS的潜在热力学。利用最近开发的COCOMO粗粒（CG）模型，我们预测缩合物的长度短至5-10个残基，然后通过实验证实，这是迄今为止观察到的最小的LLPS系统之一。自由能模型揭示了凝结的长度依赖主要是由约束熵驱动的。这个系统的简单性将为理解更多的生物现实系统提供基础。
Understanding the thermodynamics that drive liquid-liquid phase separation (LLPS) is quite important given the number of diverse biomolecular systems undergoing this phenomenon. Many studies have focused on condensates of long polymers, but very few systems of short-polymer condensates have been observed and studied. Here, we study a short-polymer system of various lengths of poly-adenine RNA and peptides formed by the RGRGG sequence repeats to understand the underlying thermodynamics of LLPS. Using the recently developed COCOMO coarse-grained (CG) model, we predicted condensates for lengths as short as 5–10 residues, which was then confirmed by experiment, making this one of the smallest LLPS systems yet observed. A free-energy model reveals that the length dependence of condensation is driven primarily by entropy of confinement. The simplicity of this system will provide the basis for understanding more biologically realistic systems.