Purification and characterization of an insect antibacterial peptide, defensin, expressed in Saccharomyces cerevisiae = Saccharomyces cerevisiae에서 발현한 곤충 항균펩티드, defensin의 정제 및 특성 조사

Abstract

We investigated the biochemical properties of insect defensin expressed and secreted from Saccharomyces cerevisiae. The defensin showed extremely high resistance to boiling for up to 30 min and to pH values tested from 2.0 to 12.0. The treatment of defensin with various proteases abolished antibacterial activity. However, amylases, cellulase, lipase and catalase had no effect on the activity. The defensin was purified to homogeneity through ammonium sulfate concentration of culture supernatant, SP-Sepharose column chromatography and RP-HPLC. Tricin-SDS-PAGE analysis revealed that the molecular weight of the defensin was about 4.0 kDa. The antibacterial activity of the purified defensin was verified by renaturation of stained gel and gel pouring assay using Micrococcus luteus as a test organism.