Molecular cloning, sequence analysis and expression of the gene encoding an antifungal-protein from Aspergillus giganteus.

The gene encoding the precursor of a small secretory protein with antifungal activity was isolated from A. giganteus and characterized by restriction mapping, hybridization and nucleotide sequencing. The promoter contains a typical TATA-box at a distance of 135 bp upstream of the open reading frame. The open reading frame is interrupted by two small introns with conserved splice sites. The precursor of the antifungal protein (AFP) consists of 94 amino acids and appears to be processed to the mature AFP of 51 amino acids by a two-step process. Transfer of the gene into A. niger yielded only transformants with a very low expression level, probably because high-expression transformants were counterselected by the antifungal activity of the recombinant protein.