title: Overproduction of the Escherichia coli Chaperones GroEL-GroES in Rhodococcus ruber Improves the Activity and Stability of Cell Catalysts Harboring a Nitrile Hydratase.
abstract: Three combinations of molecular chaperones from Escherichia coli (i.e., DnaK-DnaJ-GrpEGroEL- GroES, GroEL-GroES, and DnaK-DnaJ-GrpE) were overproduced in E. coli BL21, and their in vitro stabilizing effects on a nitrile hydratase (NHase) were assessed. The optimal gene combination, E. coli groEL-groES (ecgroEL-ES), was introduced into Rhodococcus ruber TH3. A novel engineered strain, R. ruber TH3G was constructed with the native NHase gene on its chromosome and the heterologous ecgroEL-ES genes in a shuttle plasmid. In R. ruber TH3G, NHase activity was enhanced 37.3% compared with the control, TH3. The in vivo stabilizing effect of ecGroEL-ES on the NHase was assessed using both acrylamide immersion and heat shock experiments. The inactivation behavior of the in vivo NHase after immersion in a solution of dynamically increased concentrations of acrylamide was particularly evident. When the acrylamide concentration was increased to 500 g/l (50%), the remaining NHase activity in TH3G was 38%, but in TH3, activity was reduced to 10%. Reactivation of the in vivo NHases after varying degrees of inactivation was further assessed. The activity of the reactivated NHase was more than 2-fold greater in TH3G than in TH3. The hydration synthesis of acrylamide catalyzed by the in vivo NHase was performed with continuous acrylonitrile feeding. The final concentration of acrylamide was 640 g/l when catalyzed by TH3G, compared with 490 g/l acrylamide by TH3. This study is the first to show that the chaperones ecGroEL-ES work well in Rhodococcus and simultaneously possess protein-folding assistance functions and the ability to stabilize and reactivate the native NHases.
authors.affiliation: Key Laboratory for Industrial Biocatalysis of the Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, P.R. China.
authors.forename: Yuxuan
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Key Laboratory for Industrial Biocatalysis of the Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, P.R. China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Key Laboratory for Industrial Biocatalysis of the Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, P.R. China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Yu
authors.affiliation: Key Laboratory for Industrial Biocatalysis of the Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, P.R. China.
authors.forename: Zhongyao
authors.initials: Z
authors.lastname: Shen
mesh_terms: D020106:Acrylamide / Q000378:metabolism / Q000494:pharmacology; D000181:Acrylonitrile / Q000494:pharmacology; D055162:Biocatalysis; D018835:Chaperonin 10 / Q000235:genetics* / Q000378:metabolism; D004795:Enzyme Stability; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D006836:Hydro-Lyases / Q000737:chemistry / Q000378:metabolism*; D007218:Industrial Microbiology / Q000379:methods; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids; D017510:Protein Folding; D011994:Recombinant Proteins / Q000378:metabolism; D012240:Rhodococcus / Q000201:enzymology* / Q000235:genetics*
chemical_list: D018835:Chaperonin 10; D029968:Escherichia coli Proteins; C028715:GroE protein, E coli; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D011994:Recombinant Proteins; D020106:Acrylamide; D006836:Hydro-Lyases; C048831:nitrile hydratase; D000181:Acrylonitrile
keywords: E. coli molecular chaperones GroEL-GroES; Rhodococcus ruber; activity and stability of cell catalyst; hydration synthesis of acrylamide; nitrile hydratase