Synthesis of bovine lactoferricin B gene (LfcinB) and its expression in Escherichia coli.

Two complementary sense and antisense oligo-nucleotides, encoding bovine lactoferricin B (LfcinB) gene, were synthesized based on amino acids sequence of bovine lactoferricin B published in the Antimicrobial Peptide Database (APD). After the sense and antisense oligo-nucleotides annealed, a cohesive BamHⅠ site at 5' terminus and a cohesive Xho Ⅰ site at 3' terminus were formed. The synthetic LfcinB gene was cloned into prokaryotic expression vector pET-32a. The positive bacteria clones were ampli-fied and cultured in terrific broth (TB) medium. Then the aimed protein was expressed by 0.1 mmol/L IPTG. The result of SDS-PAGE indicated that LfcinB gene was strongly expressed in Escherichia coli BL21, and the expressed recombinant protein was in form of inclusion body. Inclusion bodies of LfcinB recombinant protein were purified. The purified inclusion bodies were renatured by TGE dialysate. Result of antibacterial test indicated that the refolded recombinant protein showed good antibacterial activity against Escherichia coli BL21 with ampicillin-resistant.