Expression and characterization of the antimicrobial peptide ABP-dHC-cecropin A in the methylotrophic yeast Pichia pastoris

摘要

Abstract ABP-dHC-cecropin A is a linear cationic peptide that exhibits antimicrobial properties. To explore a new approach for expression of ABP-dHC-cecropin A using the methylotrophic yeast Pichia pastoris, we cloned the ABP-dHC-cecropin A gene into the vector pPICZαA. The SacI-linearized plasmid pPICZαA-ABP-dHC-cecropin A was then transformed into P.?pastoris GS115 by electroporation. Expression was induced after a 96-h incubation with 0.5% methanol at 20?°C in a culture supplied with 2% casamino acids to avoid proteolysis. Under these conditions, approximately 48?mg of ABP-dHC-cecropin A was secreted into 1L (4?×?250-mL)of medium. Recombinant ABP-dHC-cecropin A was purified using size-exclusion chromatography, and 21?mg of pure active ABP-dHC-cecropin A was obtained from 1L (4?×?250-mL)of culture. Electrophoresis on 4–20% gradient gels indicated that recombinant ABP-dHC-cecropin A was secreted as a protein approximately 4?kDa in size. Recombinant ABP-dHC-cecropin A was successfully expressed, as the product displayed antibacterial and antifungal activities (based on an antibacterial assay, scanning electron microscopy, and antifungal assay) indistinguishable from those of the synthesized protein. Highlights