Abstract: Objective To construct recombinant expression plasmid with an antibacterial peptide （attacin） mature peptide gene from Musca domestica and express an antibacterial peptide attacin in Pichia pastoris. Methods The coding region of attacin mature peptide was cloned into the expression vector pPIC9K. The recombinant plasmid was linearized by digestion with SacⅠand transformed into P. pastoris GS115 by electroporation. The insert clones containing multiple copies were selected with geneticin，pha，enotype and PCR. The expression of P. pastoris GS115/pPIC9K-attacin were induced with methanol. The supernatant of the expressed protein was analyzed by SDS-PAGE and Western blotting. The anti-bacterial activity of expression product was analyzed by agarose diffusion assay. Results The expression plasmid was constructed and transformed into P. pastoris GS115. SDS-PAGE and Western blotting analysis indicated that the recombinant containing recombinant plasmid pPIC9K-attacin expressed a M_r 22 000 protein. The expression product inhibited the growth of E. coli K12D31. Conclusion The attacin gene from Musca domestica has been expressed in P. pastoris.

Key words: Musca domestica, Antibacterial peptide, Attacin, Pichia pastoris, Heterologous expression