Expression of Bactericidal/permeability-increasing Protein N-terminal cDNA of Holstein cow in Escherichia coli.

According to the Bactericidal/permeability-increasing Protein(BPI) sequence of Angus calf in GenBank,a pair of primers were designed.The N-terminal cDNA was amplified by RT-PCR from mRNA which was extracted from the polymorphonuclear neutrophils of Hostein cow.The purified cDNA was connective with expression vector pGEX-4T-1 to construct recombinant plasmid pGEX-4T-1-BPI,which was transformed into Escherichia coli BL21.The results showed that a 714 bp fragment was acquired,and there was a basic mutated group in 503rd compared with the reports.The E.coli with recombinant plasmid was induced with IPTG.The products were analyzed by SDS-PAGE,and a new protein of 52 kD was detected.Its molecular weight was the same as expected,showing the purified recombinant BPI was obtained successfully.