Understanding the Coacervate-to-Vesicle Transition of Globular Fusion Proteins to Engineer Protein Vesicle Size and Membrane Heterogeneity
Understanding the Coacervate-to-Vesicle Transition of Globular Fusion Proteins to Engineer Protein Vesicle Size and Membrane Heterogeneity
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DOI：
10.1021/acs.biomac.9b00773
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发表时间：
2019-09-01
影响因子：
6.2
通讯作者：
Champion, Julie A.
中科院分区：
文献类型：
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作者：
Jang, Yeongseon;Hsieh, Ming-Chien;Champion, Julie A.
富含蛋白质的凝聚体是与水相分离的液相，被自然界用于区隔，最近被工程师用于输送和配方应用。它们还作为更复杂结构（如囊泡）组装路径的中间阶段。由球状蛋白与富含谷氨酸的亮氨酸拉链（globular -Z(E)）和富含精氨酸的亮氨酸拉链与弹性蛋白样多肽（Z(R)-ELP）融合而成的重组融合蛋白复合物，随着水溶液温度的升高，呈现出从可溶性到中间凝聚期，最后到囊泡的不同相。我们利用动态光散射和显微镜技术以及数学模型研究了不同温度下融合蛋白复合物的相变动力学。我们通过在支持凝聚的中等温度下老化溶液来控制凝聚的生长，并证实凝聚液滴的大小决定了进一步加热后形成的囊泡的大小。基于对相变的理解，我们开发了一种策略，通过在囊泡转变之前简单混合含有两种不同的球状融合蛋白的凝聚体，来诱导囊泡膜中球状蛋白组织的异质性。本研究为开发用于药物递送、微反应器和原始细胞应用的富含蛋白质的球状凝聚体和囊泡提供了基本的见解和实用的策略。
Protein-rich coacervates are liquid phases separate from the aqueous bulk phase that are used by nature for compartmentalization and more recently have been exploited by engineers for delivery and formulation applications. They also serve as an intermediate phase in an assembly path to more complex structures, such as vesicles. Recombinant fusion protein complexes made from a globular protein fused with a glutamic acid-rich leucine zipper (globule-Z(E)) and an arginine-rich leucine zipper fused with an elastin-like polypeptide (Z(R)-ELP) show different phases from soluble, through an intermediate coacervate phase, and finally to vesicles with increasing temperature of the aqueous solution. We investigated the phase transition kinetics of the fusion protein complexes at different temperatures using dynamic light scattering and microscopy, along with mathematical modeling. We controlled coacervate growth by aging the solution at an intermediate temperature that supports coacervation and confirmed that the size of the coacervate droplets dictates the size of vesicles formed upon further heating. With this understanding of the phase transition, we developed strategies to induce heterogeneity in the organization of globular proteins in the vesicle membrane through simple mixing of coacervates containing two different globular fusion proteins prior to the vesicle transition. This study gives fundamental insights and practical strategies for development of globular protein-rich coacervates and vesicles for drug delivery, microreactors, and protocell applications.