The pTrcHis2 plasmids are pBR322-derived expression vectors designed for efficient recombinant protein expression and purification in E. coli. High levels of expression are possible using the trc (trp-lac) promoter (Egon et al., 1983) and the rrnB anti-termination region (Li et al., 1984). The trc promoter contains the –35 region of the trp promoter together with the –10 region of the lac promoter (Brosius et al., 1985; Egon et al., 1983; Mulligan et al., 1985). To regulate expression, the gene encoding Lac repressor (lacIq) is provided in the pTrcHis2 vectors, allowing regulation of the trc promoter regardless of whether the host strain contains a gene encoding the Lac repressor.

Isopropyl-Beta-D-thiogalactopyranoside (IPTG) is used to induce expression of your gene. Translation is enhanced by the bacteriophage T7 gene 10 translation enhancer and a minicistron that provides highly efficient translational restart into the open reading frame of the multiple cloning site. DNA inserts are positioned downstream and in frame with the initiation ATG and a C-terminal fusion peptide. The C-terminal peptide encodes the myc epitope and six histidine residues that function as a metal binding site in the expressed protein.