Institute of Biosciences and Bioresources, Division of Perugia, National Research Council, Perugia, Italy.
Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino (PU), Italy.
Biotechnol J. 2024 Jan;19(1):e2300363. doi: 10.1002/biot.202300363. Epub 2023 Oct 13.
The future of biomaterial production will leverage biotechnology based on the domestication of cells as biological factories. Plants, algae, and bacteria can produce low-environmental impact biopolymers. Here, two strategies were developed to produce a biopolymer derived from a bioengineered vacuolar storage protein of the common bean (phaseolin; PHSL). The cys-added PHSL* forms linear-structured biopolymers when expressed in the thylakoids of transplastomic tobacco leaves by exploiting the formation of inter-chain disulfide bridges. The same protein without signal peptide (ΔPHSL*) accumulates in Escherichia coli inclusion bodies as high-molar-mass species polymers that can subsequently be oxidized to form disulfide crosslinking bridges in order to increase the stiffness of the biomaterial, a valid alternative to the use of chemical crosslinkers. The E. coli cells produced 300 times more engineered PHSL, measured as percentage of total soluble proteins, than transplastomic tobacco plants. Moreover, the thiol groups of cysteine allow the site-specific PEGylation of ΔPHSL*, which is a desirable functionality in the design of a protein-based drug carrier. In conclusion, ΔPHSL* expressed in E. coli has the potential to become an innovative biopolymer.
生物材料生产的未来将利用基于细胞驯化的生物技术，将其作为生物工厂。植物、藻类和细菌可以生产低环境影响的生物聚合物。在这里，开发了两种策略来生产源自普通豆（菜豆球蛋白；PHSL）的生物工程化液泡储存蛋白的生物聚合物。在通过利用形成链间二硫键桥来在转基因质体烟草叶的类囊体中表达添加半胱氨酸的 PHSL时，其形成线性结构的生物聚合物。没有信号肽的相同蛋白（ΔPHSL）作为高分子量的物种聚合物在大肠杆菌包涵体中积累，随后可以被氧化以形成二硫键交联桥，从而增加生物材料的刚性，这是替代使用化学交联剂的有效方法。与转基因烟草植物相比，大肠杆菌细胞产生的工程 PHSL 多 300 倍，其以总可溶性蛋白的百分比来衡量。此外，半胱氨酸的巯基允许 ΔPHSL的定点聚乙二醇化，这是设计基于蛋白质的药物载体的理想功能。总之，在大肠杆菌中表达的 ΔPHSL有可能成为一种创新的生物聚合物。
