Mussels Fabricate Porous Glues via Multiphase Liquid-Liquid Phase Separation of Condensates ARTICLE
Mussels Fabricate Porous Glues via Multiphase Liquid-Liquid Phase Separation of Condensates ARTICLE
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DOI：
10.1021/acsnano.2c08410
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发表时间：
2022-11-22
期刊：
影响因子：
17.1
通讯作者：
Harrington, Matthew J.
中科院分区：
文献类型：
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作者：
Renner-Rao, Max;Jehle, Franziska;Harrington, Matthew J.
贻贝（Mytilus edulis）在潮间带的海洋栖息地用一种叫做足丝斑块的多孔水下胶水粘附在坚硬的表面上。该斑块是生物启发水下胶的既定角色模型，并且包含至少六种蛋白质，其中大多数是高度阳离子的并且富含后修饰的氨基酸3，4-二羟基苯丙氨酸（DOPA）。虽然对斑块粘附的化学性质了解很多，但对天然斑块形成过程了解较少。在这里，我们使用3D电子显微镜成像研究了斑块的结构和形成，揭示了在蛋白质填充的分泌囊泡的分泌过程中自发形成的微孔和纳米孔。为了更好地理解这一过程，我们开发了一种方法来纯化完整的分泌囊泡在体外组装研究。我们发现每个囊泡都含有一种硫酸盐相关的液体冷凝物，由类似于9种富含组氨酸和/或多巴的蛋白质组成，这些蛋白质可能是构建斑块所需的成分。在与自然组装相关的特定缓冲条件下破裂囊泡导致不同蛋白质的受控多相液-液相分离（LLPS），从而形成具有共存液滴的连续相。通过连续相的pH依赖性交联阻止液滴相的快速粗化，产生天然的固体多孔“微斑”，其中液滴蛋白质作为流体冷凝物保留在孔内。结果表明，组氨酸去质子化和硫酸盐的数字突出缩合物交联。蒸馏的概念表明，相分离与可调交联动力学相结合，可以有效地通过自组装微制造分级多孔材料。
Mussels (Mytilus edulis) adhere to hard surfaces in intertidal marine habitats with a porous underwater glue called the byssus plaque. The plaque is an established role model for bioinspired underwater glues and comprises at least six proteins, most of which are highly cationic and enriched in the post-translationally modified amino acid 3,4-dihydroxyphenylalanine (DOPA). While much is known about the chemistry of plaque adhesion, less is understood about the natural plaque formation process. Here, we investigated plaque structure and formation using 3D electron microscopic imaging, revealing that micro-and nanopores form spontaneously during secretion of protein-filled secretory vesicles. To better understand this process, we developed a method to purify intact secretory vesicles for in vitro assembly studies. We discovered that each vesicle contains a sulfate-associated fluid condensate consisting of similar to 9 histidine-and/or DOPA-rich proteins, which are presumably the required ingredients for building a plaque. Rupturing vesicles under specific buffering conditions relevant for natural assembly led to controlled multiphase liquid-liquid phase separation (LLPS) of different proteins, resulting in formation of a continuous phase with coexisting droplets. Rapid coarsening of the droplet phase was arrested through pH-dependent cross-linking of the continuous phase, producing native like solid porous "microplaques" with droplet proteins remaining as fluid condensates within the pores. Results indicate that histidine deprotonation and sulfates figure prominently in condensate cross-linking. Distilled concepts suggest that combining phase separation with tunable cross-linking kinetics could be effective for microfabricating hierarchically porous materials via self-assembly.