Antimicrobial peptides (AMPs) are peptides exhibiting broad-spectrum antimicrobial activities and considered as potential therapeutic agents. LsGRP1C, a novel AMP derived from defense-related LsGRP1 protein of Lilium, was proven to inhibit kinds of bacteria and fungi via alteration of microbial membrane permeability and induction of fungal programmed cell death-like phenomena by in vitro assays using synthetic LsGRP1C. In this study, the prokaryotic production of LsGRP1C recombinant protein containing an N-terminal fusion partner of the yeast small ubiquitin-like modifier (SUMO) was achieved by using optimized Escherichia coli host and purification buffer system, which lead to a high yield of soluble SUMO-LsGRP1C fusion protein. In vitro assay revealed that E. coli-expressed SUMO-LsGRP1C exhibited even better antifungal activity as compared to synthetic LsGRP1C. Meanwhile, the ability of SUMO-LsGRP1C in conducting fungal membrane permeabilization and programmed cell death was verified by SYTOX Green staining and 4',6-diamidino-2-phenylindole staining/terminal deoxynucleotidyl transferase dUTP nick-end labeling assays, respectively, indicating that E. coli-expressed SUMO-LsGRP1C shares identical modes of action with synthetic LsGRP1C. Herein, this E. coli expression system enables the effective and convenient production of antimicrobial LsGRP1C in a form of SUMO-fused recombinant protein.
Keywords: Antimicrobial peptide; Escherichia coli expression system; LsGRP1C; SUMO fusion partner.