Expression Optimization and Purification of Glutamate Endopeptidase from halo-thermo tolerant Bacillus licheniformis SL-1

Aims and Background: Glutamate-specific endopeptidase (GSE, EC 3.4.21.19) is belonging to the serine protease family enzymes. A glutamate-specific endopeptidase has the ability to cleavage peptide bonds for the protein structure analysis, solid phase synthesis of peptides and preparation of nanotubes. The purpose of this investigation was to produce glutamate endopeptidase enzyme from the Bacillus licheniformis SL-1from isolated from Aran-Bidgol salt lake in Iran. Material and Methods: In this study, the expression of glutamate-endopeptidase enzyme from the B. licheniformis SL-1 wasinvestigated in periplasmic spaces of E. coli BL21 in different temperature (16ᴼC, 20ᴼC, 37ᴼC) and different concentrations of inducer (0.4, 1, 2 mM).  Results: Analysis the results demonstrated that periplasmic and soluble expression of glutamate endopeptidase was observed in E. coli BL21at 37ᴼC and 2 mM concentration of IPTG. Conclusion: Qualitative investigation of the expression results revealed that the expression of the enzyme is temperature-dependant and requires higher concentrations of IPTG. This preliminary study provides the possibility of recombinant enzyme production in E. coli BL21 expression system. In order to produce large scale of this enzyme, other expression systems as well as alternative purification systems can be studied.