Evalution of tree frog antimicrobial peptide production by bacterial and plant expression system

Antimicrobial peptides play a role in innate immune system in all living organisms. Rhacoporin-2, a novel AMP from the skin secretion of Rhacophorus feae, shows an antimicrobial activity against both Gram-positive and Gram-negative bacteria. Contrastingly, it is relatively unharmful to mammalian red blood cell. Thus, it has a potential to be used as pharmaceutical agent. SUMO fusion system is employed for Rhacoporin-2 production. Therefore, the objective of this study is to evaluate the recombinant peptide, SUMO-Rhacoporin2, production by bacterial expression system and plant expression system. In Escherichia coli system, the total 131 µg/L of Rhacoporin2 with 85% purity was produced and the peptide exhibited the antibacterial activity against Salmonella Typhimurium at 8 µM. Hence, SUMO fusion system was effective for antimicrobial peptide production by bacterial system. For the recombinant peptide production in 2 plant hosts, Lemna minor and Arabidopsis thaliana, the results showed that the very low amount of recombinant peptide, 44.8 µg, was synthesized from 100 mg fresh duckweed, whereas, SUMOstar fusion tag for peptide production was unsuccessful in Arabidopsis. Therefore, SUMO fusion system was ineffective in these two species. However, plant system is still promising due to the low cost of production for therapeutic agents.