School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Drive NW, Atlanta, Georgia 30332, United States.
Biomacromolecules. 2021 Jan 11;22(1):116-125. doi: 10.1021/acs.biomac.0c00671. Epub 2020 Sep 4.
Protein vesicles can be synthesized by mixing two fusion proteins: an elastin-like polypeptide (ELP) fused to an arginine-rich leucine zipper (Z) with a globular, soluble protein fused to a glutamate-rich leucine zipper (Z). Currently, only fluorescent proteins have been incorporated into vesicles; however, for protein vesicles to be useful for biocatalysis, drug delivery, or biosensing, vesicles must assemble from functional proteins that span an array of properties and functionalities. In this work, the globular protein was systematically changed to determine the effects of the surface charge and size on the self-assembly of protein vesicles. The formation of microphases, which included vesicles, coacervates, and hybrid structures, was monitored at different assembly conditions to determine the phase space for each globular protein. The results show that the protein surface charge has a small effect on vesicle self-assembly. However, increasing the size of the globular protein decreases the vesicle size and increases the stability at lower Z/Z molar ratios. The phase diagrams created can be used as guidelines to incorporate new functional proteins into vesicles. Furthermore, this work reports catalytically active enzyme vesicles, demonstrating the potential for the application of vesicles as biocatalysts or biosensors.
一种弹性蛋白样多肽（ELP）与富含精氨酸的亮氨酸拉链（Z）融合，另一种球状可溶性蛋白与富含谷氨酸的亮氨酸拉链（Z）融合。目前，只有荧光蛋白被掺入囊泡中；然而，为了使蛋白质囊泡在生物催化、药物传递或生物传感方面有用，囊泡必须由具有一系列性质和功能的功能性蛋白质组装而成。在这项工作中，系统地改变了球状蛋白，以确定表面电荷和大小对蛋白质囊泡自组装的影响。在不同的组装条件下监测微相的形成，包括囊泡、凝聚物和混合结构，以确定每种球状蛋白的相空间。结果表明，蛋白质表面电荷对囊泡自组装的影响很小。然而，增加球状蛋白的大小会降低囊泡的大小，并在较低的 Z/Z 摩尔比下增加稳定性。创建的相图可用作将新的功能性蛋白质纳入囊泡的指南。此外，这项工作还报道了具有催化活性的酶囊泡，证明了囊泡作为生物催化剂或生物传感器应用的潜力。
