Biochemical and Molecular Characterization of an Antifungal Protein from Tenebrio molitor Larvae

Abstract

We have purified an antifungal protein, named tenecin 3, from meal worms (larvae of Tenebrio molitor) by a combination of heat treatment, C18 reverse-phase open column chromatography, and C18 reverse-phase high performance liquid chromatography. A cDNA region containing coding information for tenecin 3 was identified by means of PCR-amplification with a degenerate primer inferred from its partial amino acid sequence. Analysis of cDNA indicated that tenecin 3 was composed of 78 amino acids and generated from a 96-amino acid precursor molecule. Tenecin 3 is rich in glycine (43.6% in molar percent) and has a repeated motif of Gly-X-X-Gly where X denotes glutamine, histidine, or leucine. This motif reiterates 11 times in tenecin 3. Comparative analysis of tenecin 3 and other antifungal proteins from different insects provides evidence for the existence of a famiJy of antifungal proteins.