Georgiou G, Valax P
Department of Chemical Engineering, University of Texas, Austin, 78712, USA.
Curr Opin Biotechnol. 1996 Apr;7(2):190-7. doi: 10.1016/s0958-1669(96)80012-7.
Many heterologous polypeptides fail to fold into their native state when expressed in Escherichia coli; instead, they are either degraded by the cellular proteolytic machinery or accumulate in insoluble form, typically as inclusion bodies. Misfolding is a particularly vexing problem in the expression of mammalian proteins, especially those that are composed of multiple subunits, have several disulfide bonds, or contain prosthetic groups. Fortunately, bacteria exhibit a remarkable physiological plasticity that can be successfully exploited to improve protein folding. Significant yields of active heterologous proteins have been obtained through strategies that include the co-expression of homologous or heterologous folding accessory proteins, the optimization of growth conditions, and the use of fusion proteins. A flood of recent reports documenting the successful production of complex eukaryotic proteins in active form have demonstrated that bacteria can provide the proper environment for the folding of the vast majority of recombinant polypeptides.
许多异源多肽在大肠杆菌中表达时无法折叠成天然状态；相反，它们要么被细胞蛋白水解机制降解，要么以不溶性形式积累，通常形成包涵体。错误折叠是哺乳动物蛋白表达中一个特别棘手的问题，尤其是那些由多个亚基组成、有多个二硫键或含有辅基的蛋白。幸运的是，细菌表现出显著的生理可塑性，可以成功利用这一点来改善蛋白质折叠。通过包括共表达同源或异源折叠辅助蛋白、优化生长条件以及使用融合蛋白等策略，已经获得了大量活性异源蛋白。最近大量报道记录了以活性形式成功生产复杂真核蛋白的情况，这表明细菌可以为绝大多数重组多肽的折叠提供合适的环境。
