Study on the Synthesis of Lactoferricin Bovine (Lfcin B) Gene and Its Expression in Microzyme

[Objective] The research aimed to provide basis for clinical research and cure the infection caused by some pathogenic microorganisms.[Method] According to the amino acid sequence of Lfcin B, the gene was synthesized by using chemical synthesis method and cloned into pPIC9K vector. Then it was transformed into competent cells of microzyme GS115 and high-copy microzyme transformants were screened out by using resistant selective marker G418. The expression of the recombinant Lfcin B gene was induced by methanol and the expression conditions of target protein Lfcin B were detected by Tricine- SDS- PAGE and at the same time the antibacterial activity of expression product was detected by bacteriostatic test in vitro. [Result] An expected specific band with the length of about 560 bp was amplified by the extracted microzyme DNA. The target gene was successfully cloned into pPIC9K vector and transformed into microzyme GS115 for obtaining expression. The antibacterial activity of antibacterial peptide of Lfcin B in expression supernatant of the recombinant yeast to Salmonella enteritidis was 42.857 IU/ml, which indicated that yeast expression vector of Lfcin B gene was constructed successfully. [Conclusion] This research proved that it was feasible to construct eukaryotic expression vector by directly synthesizing DNA coded by Lfcin B by using chemical synthesis method and preparing Lfcin B by biological fermentation engineering.