Isolation and characterization of the Aspergillus oryzae gene encoding aspergillopepsin O

We have cloned and determined the nucleotide sequence of a genomic DNA segment from Aspergillus oryzae which contains pepO, the gene encoding the aspartic proteinase, aspergillopepsin O (PEPO). The organization of pepO is strikingly similar to that of pepA from A. niger var. awamori (previously called A. awamori) in that both are composed of four exons and three introns with virtually identical lengths, and the positions of the introns are exactly conserved. From the deduced amino acid (aa) sequence, it appears that PEPO, like other fungal aspartic proteinases, is synthesized as a zymogen containing a putative N-terminal prepro-region of 77 aa followed by a mature protein of 327 aa. Southern blotting experiments suggest that a single copy of pepO exists in the A. oryzae genome.