3.5 Periplasmic secretion of FPOX by signal PelB
FPOX successfully expressed in E. coli by connecting PelB sequence peptide in the protein upstream. PelB signal peptide acts as a targeting and recognition signal that mediated the transfer of recombinant FPOX across the inner membrane to periplasm space. Within the periplasm, the PelB signal peptide was cut by specific signal peptidase and the recombinant protein has about 2.3 KDa lower weight after cutting signal peptide. The recombinant FPOX was secreted in the periplasmic space, however, the main part of FPOX remained in the inclusion bodies. As showed in Fig.5, the amount of periplasmic protein in shuffle was higher than of that in BL21. The most level of protein in the periplasmic space was observed in sample treated with lysozyme in shuffle that contributes to break the cell wall.