Ho Ka M, Lim Boon L
Department of Zoology, the University of Hong Kong, Pokfulam Road, Hong Kong, China.
Protein Expr Purif. 2003 Dec;32(2):293-301. doi: 10.1016/j.pep.2003.08.002.
A dual expression system for overexpressing two proteins by a single cell strain has been developed in Bacillus subtilis. This dual expression system combines the phi105MU331 prophage system and a plasmid system within a single cell. Protein expression by the prophage system is heat inducible, while that of the plasmid system is constitutive. Three candidate genes, BPN, BT, and amyE, all of Bacillus origin, were used as test models. Seven strains (BPN, BT, AMY, BS168K, MU331K, BPNK, and BTK) were constructed to investigate the influences of the prophage system and the plasmid system on each other, and to compare the efficiency of the individual expression systems with that of the dual expression system. Individually, the yield of the plasmid system is higher than that of the prophage system, which could be attributed to the constitutive nature of the expression of the plasmid system. Nonetheless, for the dual expression strains, the expression of two enzymes in a single fermentation run can reduce costs in facilities, manpower, and utilities. Fed-batch fermentation of BPNK strains confirmed the feasibility of applying this dual expression system in industrial-scale production.
已在枯草芽孢杆菌中开发出一种通过单一细胞菌株过表达两种蛋白质的双表达系统。该双表达系统在单个细胞内将phi105MU331前噬菌体系统和质粒系统结合起来。前噬菌体系统的蛋白质表达是热诱导型的，而质粒系统的表达是组成型的。三个均来源于芽孢杆菌的候选基因BPN、BT和amyE被用作测试模型。构建了七个菌株（BPN、BT、AMY、BS168K、MU331K、BPNK和BTK），以研究前噬菌体系统和质粒系统对彼此的影响，并将单个表达系统的效率与双表达系统的效率进行比较。单独来看，质粒系统的产量高于前噬菌体系统，这可能归因于质粒系统表达的组成型性质。尽管如此，对于双表达菌株而言，在单次发酵过程中表达两种酶可以降低设施、人力和公用事业方面的成本。BPNK菌株的补料分批发酵证实了将这种双表达系统应用于工业规模生产的可行性。
