中国生物工程杂志

Insect defensins as a sort of defesins are a family of novel peptides with anti-extrogenous pathogen activities. They are a class of small cationic antibiotic peptides that have abundant of arginine (Arg). Insect defensins selectively kill Gram-positive bacteria. Using the preferential condon of Pichia pastoris, a novel antibacterial peptide Musca domestica Defensin (des-hf) 140bp in length was designed and synthesized according to the sequence from GenBank（AY260152）. The modified antibacterial peptide gene was cloned into the pPICZα-A vector to construct the recombinant expression vector pPICZα-A-des-hf and then transformed into yeast host strain SMD1168. Under the control of the promoter AOX1 (alcohol oxidase 1), the protein with a similar molecular weight to native antibacterial peptide was expressed and secreted into the supernatant. Des-hf peptide showed potent antibacterial activity against Staphylococcus aureus in elementary Secretion expression.