Production of bioactive sheep β-defensin-1 in Pichia pastoris

Previous research has shown that sheep β-defensin-1 (sBD-1), a small cationic peptide with a broad range of antimicrobial activities, could inhibit the growth of both Gram-positive and Gram-negative bacteria as well as that of fungi. In order to increase the yield of current ovine defensin purification methods, mature sBD-1 (msBD-1) was added with a 6-His tag on the C-terminus (msBD-1-T) and expressed in Pichia pastoris in the presented work. The msBD-1 and msBD-1-T were expressed in the Pichia pastoris. Both msBD-1 and msBD-1-T were purification, and the two peptides were used to inhibit Escherichia coli, Staphylococcus aureus, Proteus vulgaris, Pseudomonas aeruginosa, and Shigella flexneri. The antimicrobial activity of the 6-His tagged msBD-1-T peptide was not significantly different from that of the native msBD-1 peptide. The two peptides could inhibit the growth of Escherichia coli, Staphylococcus aureus, Proteus vulgaris, Pseudomonas aeruginosa, and Shigella flexneri with equal efficiency as well as chemoattractant function. In addition, the yield of purified 6-His-tagged msBD-1 was greater than that of msBD-1. The presented method might be a more efficient approach to produce bioactive sBD-1.