The Construction And Functional Verification Of Self-Induced Protein Expression System Based On Signal Molecule AI-2

The pET system is currently the most widely used prokaryotic expression system in the laboratory.The target gene is cloned into the pET plasmid vector and controlled by the strong bacteriophage T7 transcription and translation signals.However,this system requires IPTG induction and easy to form inclusion bodies.In this paper,the pET vector was transformed by introducing the promoter of AI-2 quorum sensing receptor protein LsrR to successfully construct the pXWZ-1 vector without induction.In order to verify the expression ability of the recombinant plasmid,E.coli BL21(DE3)was used as the host strain,and the fluorescence intensity of GFPuv expressed by pET28a-GFPuv and pXWZ-1-GFPuv was monitored in real time under the same conditions,and the pET28a-Lac Z was compared and monitored by real time and pXWZ-1-Lac Zβ-galactosidase activity under the same conditions,indicating that the pXWZ-1 system can achieve a large amount of expression of the target protein under induction-free conditions and the expression efficiency is higher than that of the pET system;The SDS-PAGE images of pET28a-QseB and pXWZ-1-QseB protein expression,SDS-PAGE images of crushed supernatant and precipitate at 16℃、28℃ and 37℃ indicates that the pXWZ-1system can be greatly improved compared to pET series vectors Solubility of target protein,less protein misfolding and low temperature induction is not required.Compared with the pET system that requires IPTG induction,the induction-free pXWZ-1 expression system constructed after introducing the promoter of AI-2 quorum sensing receptor protein LsrR has many advantages such as high protein expression,less formation of inclusion bodies,does not require low temperature induction,etc.It provides a potential idea for the industrialization needs of large-scale fermentation production of recombinant proteins.