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 ...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.展开更多
Disulfide-bond A oxidoreductase-like protein(DsbA-L)is a molecular chaperone involved in the multimeri-zation of adiponectin.Recent studies have found that DsbA-L is related to metabolic diseases including gestational...Disulfide-bond A oxidoreductase-like protein(DsbA-L)is a molecular chaperone involved in the multimeri-zation of adiponectin.Recent studies have found that DsbA-L is related to metabolic diseases including gestational diabetes mellitus(GDM),and can be regulated by peroxisome proliferator-activated receptorγ(PPARγ)agonists;the specific mechanism,however,is uncertain.Furthermore,the relationship between DsbA-L and the novel adipokine chemerin is also unclear.This article aims to investigate the role of DsbA-L in the improvement of insulin resistance by PPARγagonists in trophoblast cells cultured by the high-glucose simulation of GDM placenta.Immunohistochemistry and western blot were used to detect differences between GDM patients and normal pregnant women in DsbA-L expression in the adipose tissue.The western blot technique was performed to verify the relationship between PPARγagonists and DsbA-L,and to explore changes in key molecules of the insulin signaling pathway,as well as the effect of chemerin on DsbA-L.Results showed that DsbA-L was significantly downregulated in the adipose tissue of GDM patients.Both PPARγagonists and chemerin could upregulate the level of DsbA-L.Silencing DsbA-L affected the function of rosiglitazone to promote the phosphatidylinositol 3-kinase(PI3K)-protein kinase B(PKB)/AKT pathway.Therefore,it is plausible to speculate that DsbA-L is essential in the environment of PPARγagonists for raising insulin sensitivity.Overall,we further clarified the mechanism by which PPARγagonists improve insulin resistance.展开更多
Disulfide bond formation protein A （DsbA） is one of the important helper proteins for folding in protein synthesis in vivo. In this study, purification of recombinant DsbA was investigated by examining four importan...Disulfide bond formation protein A （DsbA） is one of the important helper proteins for folding in protein synthesis in vivo. In this study, purification of recombinant DsbA was investigated by examining four important factors with Box-Behnken design method, a statistic-based design of experiments. The optimal operation conditions were obtained by adopting the effectiveness coefficient method on the multi-objective problem, which takes the protein recovery, purification efficiency and throughput of ion-exchange chromatography into account. After the optimization, protein recovery of 96.8% and purity higher than 95% DsbA was achieved, and the productivity was （377.9±1.7） mg soluble DsbA per liter broth. The purified protein was identified by peptide mass fingerprinting matching the record of gil2624856, a mutant of DsbA. The DsbA was preliminarily applied to the refolding of denatured lysozyme in vitro.展开更多
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）.
文摘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.
基金Project supported by the National Key Research and Development Program of China(Nos.2016YFC1000405 , 2018YFC1002903)。
文摘Disulfide-bond A oxidoreductase-like protein(DsbA-L)is a molecular chaperone involved in the multimeri-zation of adiponectin.Recent studies have found that DsbA-L is related to metabolic diseases including gestational diabetes mellitus(GDM),and can be regulated by peroxisome proliferator-activated receptorγ(PPARγ)agonists;the specific mechanism,however,is uncertain.Furthermore,the relationship between DsbA-L and the novel adipokine chemerin is also unclear.This article aims to investigate the role of DsbA-L in the improvement of insulin resistance by PPARγagonists in trophoblast cells cultured by the high-glucose simulation of GDM placenta.Immunohistochemistry and western blot were used to detect differences between GDM patients and normal pregnant women in DsbA-L expression in the adipose tissue.The western blot technique was performed to verify the relationship between PPARγagonists and DsbA-L,and to explore changes in key molecules of the insulin signaling pathway,as well as the effect of chemerin on DsbA-L.Results showed that DsbA-L was significantly downregulated in the adipose tissue of GDM patients.Both PPARγagonists and chemerin could upregulate the level of DsbA-L.Silencing DsbA-L affected the function of rosiglitazone to promote the phosphatidylinositol 3-kinase(PI3K)-protein kinase B(PKB)/AKT pathway.Therefore,it is plausible to speculate that DsbA-L is essential in the environment of PPARγagonists for raising insulin sensitivity.Overall,we further clarified the mechanism by which PPARγagonists improve insulin resistance.
基金Supported by the National Natural Science Foundation of China （21036005）.
文摘Disulfide bond formation protein A （DsbA） is one of the important helper proteins for folding in protein synthesis in vivo. In this study, purification of recombinant DsbA was investigated by examining four important factors with Box-Behnken design method, a statistic-based design of experiments. The optimal operation conditions were obtained by adopting the effectiveness coefficient method on the multi-objective problem, which takes the protein recovery, purification efficiency and throughput of ion-exchange chromatography into account. After the optimization, protein recovery of 96.8% and purity higher than 95% DsbA was achieved, and the productivity was （377.9±1.7） mg soluble DsbA per liter broth. The purified protein was identified by peptide mass fingerprinting matching the record of gil2624856, a mutant of DsbA. The DsbA was preliminarily applied to the refolding of denatured lysozyme in vitro.
