EXPRESSION OF AN INSECT ANTIFUNGAL PROTEIN OF TENEBRIO-MOLITOR IN ESCHERICHIA-COLI

Abstract

We previously isolated an antifungal protein, termed tenecin 3, from Tenebrio molitor larvae, which inhibits growth of the fungus Candia albicans. By using a cDNA sequence for tenecin 3, in this study, we have constructed plasmids expressing recombinant tenecin 3 proteins in Escherichia coli. The recombinant tenecin 3 was expressed as fusions to maltose-binding protein (MBP) which were able to produce tenecin 3 and MBP moieties by cleavage with factor Xa protease. The MBP-tenecin 3 fusion protein showed good repression of the growth of C. albicans and Cryptococus neoformans, although the cleavage with factor Xa showed more inhibition on the fungal growth. The fusion protein, however, did not inhibit the growth of Aspergillus nidulans and Saccharomyces cerevisiae regardless of the treatment with factor Xa, The results indicate that the MBP fusion protein expression system provides a rapid and simple method for obtaining large quantities of active recombinant tenecin 3 in E. coli.