Diffusion determines the turnover of biomolecules in liquid-liquid phase-separated condensates. We considered the mean square displacement and thus the diffusion constant for simple model systems of peptides GGGGG, GGQGG, and GGVGG in aqueous solutions after phase separation by simulating atomic-level models. These solutions readily separate into aqueous and peptide-rich droplet phases. We noted the effect of the peptides being in a solvated, surface, or droplet state on the peptide’s diffusion coefficients. Both sequence and peptide conformational distribution were found to influence diffusion and condensate turnover in these systems, with sequence dominating the magnitude of the differences. We found that the most compact structures for each sequence diffused the fastest in the peptide-rich condensate phase. This model result may have implications for turnover dynamics in signaling systems.

中文翻译：

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生物分子凝聚物中的肽扩散


扩散决定了液-液相分离冷凝物中生物分子的周转。我们通过模拟原子级模型，考虑了相分离后水溶液中肽 GGGGG、GGQGG 和 GVGGG 的简单模型系统的均方位移和扩散常数。这些溶液很容易分离成水相和富含肽的液滴相。我们注意到肽处于溶剂化状态、表面状态或液滴状态对肽扩散系数的影响。发现序列和肽构象分布都会影响这些系统中的扩散和冷凝物周转，其中序列主导了差异的大小。我们发现每个序列最紧凑的结构在富含肽的凝聚相中扩散最快。该模型结果可能对信号系统中的周转动态产生影响。