Hydrogen bond guidance and aromatic stacking drive liquid-liquid phase separation of intrinsically disordered histidine-rich peptides
Hydrogen bond guidance and aromatic stacking drive liquid-liquid phase separation of intrinsically disordered histidine-rich peptides
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DOI：
10.1038/s41467-019-13469-8
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发表时间：
2019-11-29
影响因子：
16.6
通讯作者：
Miserez, Ali
中科院分区：
文献类型：
--
作者：
Gabryelczyk, Bartosz;Cai, Hao;Miserez, Ali
内在无序蛋白质的液液相分离过程涉及细胞内无膜细胞器和细胞外组织。尽管对LLPS的了解越来越多，但这一过程背后的分子水平机制仍未完全建立。在这里，我们使用富含组氨酸的鱿鱼喙蛋白（HBPs）作为模型IDP来阐明LLPS的分子相互作用。我们表明，HBPs的LLPS介导的特定模块重复。分离相的形态（液体状相对于水凝胶）与重复的疏水性相关。溶液状态的NMR表明，LLPS是一个多步骤的过程中发起的组氨酸残基的去质子化，其次是短暂的氢键与酪氨酸，并最终通过疏水相互作用。根据固态NMR实验，通过酪氨酸残基的芳族簇合来稳定微滴，所述酪氨酸残基在纳米至微秒的时间尺度内表现出受限的分子流动性。我们的研究结果为合理设计具有LLPS能力的pH响应肽提供了指导方针，用于各种应用，包括生物启发的原始细胞和智能药物递送系统。
Liquid-liquid phase separation (LLPS) of intrinsically disordered proteins (IDPs) is involved in both intracellular membraneless organelles and extracellular tissues. Despite growing understanding of LLPS, molecular-level mechanisms behind this process are still not fully established. Here, we use histidine-rich squid beak proteins (HBPs) as model IDPs to shed light on molecular interactions governing LLPS. We show that LLPS of HBPs is mediated though specific modular repeats. The morphology of separated phases (liquid-like versus hydrogels) correlates with the repeats' hydrophobicity. Solution-state NMR indicates that LLPS is a multistep process initiated by deprotonation of histidine residues, followed by transient hydrogen bonding with tyrosine, and eventually by hydrophobic interactions. The microdroplets are stabilized by aromatic clustering of tyrosine residues exhibiting restricted molecular mobility in the nano-to-microsecond timescale according to solid-state NMR experiments. Our findings provide guidelines to rationally design pH-responsive peptides with LLPS ability for various applications, including bioinspired protocells and smart drug-delivery systems.