DsbA-DsbAmut fusion chaperon improved soluble expression of human trypsinogen-1 in Escherichia coli  

作　　者：Ye Liu Wenyong Zhang Xubin Yang Guangbo Kang Damei Wang He Huang 

机构地区：[1]Key Laboratory of System Bioengineering, Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China [2]Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China [3]College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin 300072, China [4]Gan & Lee Pharmaceuticals, Beijing 101100, China [5]Taiyuan Institute of Technology, Taiyuan 030000, China

出　　处：《Frontiers of Chemical Science and Engineering》2015年第4期511-521,共11页化学科学与工程前沿（英文版）

基　　金：Acknowledgements The present work was partially supported by the National Natural Science Foundation of China （Grant No. 31470967） and National Science and Technology Major Projects of China （Grant Nos. 2011ZX09201-301-05 and 2014ZX09508006-002-002）.

摘　　要：A co-expressing system ofDsbA-DsbAmut was suggested for the first time to enhance the soluble expression of human trypsin-1. As a control, leaderless DsbA chaperone was also co-expressed with human trypsin-1. Vectors pET39b-trypsin and pET28a-DsbA- DsbAn^ut-trypsin with the above two DsbA fusion tag were constructed. The strain with vector pET39b-trypsin expressed fusion protein DsbA-trypsin in form of inclusion bodies. While in E. coli BL21 （DE3） strain with vector pET28a-DsbA-DsbAmUt-trypsin, the soluble expression of trypsin fusion protein was achieved. Under the optimized expression conditions, the soluble fraction accounted for about 49.43% of total DsbA-DsbAmUt-trypsin proteins in crude supernatant. The purification yield was 4.15% by nickel chelating chromatography and 3.3 mg activated trypsin with a purity of 88.68% was obtained from 1 L LB broth. To detect the possible functions of DsbA series chaperons in trypsin fusion protein, we analyzed the primary three-dimensional structure of fusion proteins, mainly focusing on the compatibleness between trypsin and fusion chaperons. The results suggested that （1） besides the primary function in periplasm, leaderless DsbA or DsbAmut may also act as a signal sequences-like leader targeted to periplasm that partly relieved the pressure from fusion protein overexpression and inclusion body formation, and （2） as there was significant soluble expression of DsbA-DsbAmUt-trypsin compared with DsbA-trypsin, DsbArout may function as charge or hydrophobic balance in recombinant protein DsbA-DsbAmut- trypsin.A co-expressing system ofDsbA-DsbAmut was suggested for the first time to enhance the soluble expression of human trypsin-1. As a control, leaderless DsbA chaperone was also co-expressed with human trypsin-1. Vectors pET39b-trypsin and pET28a-DsbA- DsbAn^ut-trypsin with the above two DsbA fusion tag were constructed. The strain with vector pET39b-trypsin expressed fusion protein DsbA-trypsin in form of inclusion bodies. While in E. coli BL21 （DE3） strain with vector pET28a-DsbA-DsbAmUt-trypsin, the soluble expression of trypsin fusion protein was achieved. Under the optimized expression conditions, the soluble fraction accounted for about 49.43% of total DsbA-DsbAmUt-trypsin proteins in crude supernatant. The purification yield was 4.15% by nickel chelating chromatography and 3.3 mg activated trypsin with a purity of 88.68% was obtained from 1 L LB broth. To detect the possible functions of DsbA series chaperons in trypsin fusion protein, we analyzed the primary three-dimensional structure of fusion proteins, mainly focusing on the compatibleness between trypsin and fusion chaperons. The results suggested that （1） besides the primary function in periplasm, leaderless DsbA or DsbAmut may also act as a signal sequences-like leader targeted to periplasm that partly relieved the pressure from fusion protein overexpression and inclusion body formation, and （2） as there was significant soluble expression of DsbA-DsbAmUt-trypsin compared with DsbA-trypsin, DsbArout may function as charge or hydrophobic balance in recombinant protein DsbA-DsbAmut- trypsin.

关 键 词：DSBA DsbA-DsbAmut soluble expression trypsin CHAPERON 

分 类 号：Q786[生物学—分子生物学] Q78