Efficient Production of Yeast Cu-Zn Superoxide Dismutase in the Periplasm of Escherichia coli by Co-expression of Skp Molecular Chaperone

Abstract

Co-expression is a simultaneous expression of two or more proteins. Molecular chaperones are proteins that are naturally produced in the cell and have an essential role in restraining the aggregation of nonnative protein production. Co-expression of target protein alongside molecular chaperones is an efficient way to overcome the problems faced during the expression of recombinant proteins. The present study aims to a co-express protein highly useful in cosmetics, superoxide dismutase (SOD), in the periplasm of E. coli with molecular chaperone Skp. Superoxide dismutase and Skp were placed under the control of the different promoter and terminator systems to maintain separate expression levels. The co-expression of Skp chaperone on cell growth, SOD protein yield, and SOD enzyme activity were evaluated. Skp co-expression was found effective in all three aspects. The yield of Cu-Zn Superoxide dismutase increased from 30.92mg/L to 52.01mg/L when Skp chaperon is co-expressed. No detectable free SOD subunits were observed on western blot, which shows the method of Skp co-expression could be applied to tackle the problem of unprocessed, free protein subunits while expressing the recombinant protein in E. coli periplasm.