PluxI mutants with different promoting period and their application for quorum sensing regulated protein expression

Abstract

Quorum sensing (QS) system can dynamically control the expression of proteins along with the cell growth. The promoting period of QS system has been little focused on until now. In this study, a self-induced dynamic regulated expression (SIDRE) system was constructed in Escherichia coli. To enable the system suitable for the expression of enzymes, promoter engineering was used to obtain PluxI mutants. To test the SIDRE system, alginate lyase AL493 and esterase Est7 were used as target protein for expression. The enzyme activity of alginate lyase and esterase reached 96.38 % and 106.71 % of the control strains containing the T7 promoter. In high-density fermentation, the activity of alginate lyase expressed by the SIDRE system with PluxI(T-38C) as promoter was 4.34-fold of that expressed by the T7 promoter. Therefore, the PluxI mutants with different promoting periods and/or different strengths show great potential in both laboratory and industrial scale for protein expression.

Keywords

• Quorum sensing
• Promoter engineering
• Enzymes
• Alginate lyase
• Esterase
• High-density fermentation