High-level expression and efficient purification of the antimicrobial peptide gaegurin 4 in e. coli

Abstract: Gaegurin 4 (GGN4), an antimicrobial peptide isolated from Rana rugosa skin, was expressed in Escherichia coli as a form of inactive glutathione S-transferase (GST) fusion polypeptide. Recombinant GGN4 was obtained by enzymatic and chemical processing of the fusion protein and purification of the processed products by affinity chromatography and high performance liquid chromatography (HPLC). 2.2 mg of biologically active recombinant GGN4 was obtained from 7 liters of E. coli culture. .This strategy may be applied to preparation of other recombinant peptides which cause host cell toxicity.