Laboratory of Organic Chemistry, ETH Zurich , 8093 Zurich, Switzerland.
J Am Chem Soc. 2018 Jan 17;140(2):558-561. doi: 10.1021/jacs.7b10513. Epub 2018 Jan 2.
Self-assembling protein cages are useful as nanoscale molecular containers for diverse applications in biotechnology and medicine. To expand the utility of such systems, there is considerable interest in customizing the structures of natural cage-forming proteins and designing new ones. Here we report that a circularly permuted variant of lumazine synthase, a cage-forming enzyme from Aquifex aeolicus (AaLS) affords versatile building blocks for the construction of nanocompartments that can be easily produced, tailored, and diversified. The topologically altered protein, cpAaLS, self-assembles into spherical and tubular cage structures with morphologies that can be controlled by the length of the linker connecting the native termini. Moreover, cpAaLS proteins integrate into wild-type and other engineered AaLS assemblies by coproduction in Escherichia coli to form patchwork cages. This coassembly strategy enables encapsulation of guest proteins in the lumen, modification of the exterior through genetic fusion, and tuning of the size and electrostatics of the compartments. This addition to the family of AaLS cages broadens the scope of this system for further applications and highlights the utility of circular permutation as a potentially general strategy for tailoring the properties of cage-forming proteins.
自组装蛋白笼可用作纳米尺度的分子容器，在生物技术和医学中有广泛的应用。为了扩展这些系统的用途，人们对定制天然笼状蛋白结构和设计新蛋白结构有很大的兴趣。在这里，我们报告一种来自水生栖热菌的光解酶（Aquifex aeolicus，AaLS）的环状排列变体，它为纳米隔间的构建提供了多功能的构建模块，这些隔间易于生产、定制和多样化。拓扑改变的蛋白 cpAaLS 可自我组装成球形和管状笼状结构，其形态可以通过连接天然末端的连接子的长度来控制。此外，cpAaLS 蛋白通过在大肠杆菌中的共生产整合到野生型和其他工程化的 AaLS 组装体中，形成拼凑笼。这种共组装策略可实现腔内包裹客体蛋白、通过基因融合对外层进行修饰，以及调节隔间的大小和静电特性。该 AaLS 笼家族的这一补充拓宽了该系统的应用范围，并突出了环状排列作为一种潜在通用策略，用于调整笼状蛋白的特性。
