Cloning and expression in Saccharomyces cerevisiae of a beta-amylase gene from the oomycete Saprolegnia ferax

Genomic DNA and cDNA encoding the beta-amylase from the oomycete, Saprolegn ia ferax, were cloned into Saccharomyces cerevisiae and analyzed. The Spl. ferax beta-amylase gene consisted of a 1350 bp open reading frame, encoding a protein of 450 amino acids with a calculated mass of 49 353 Da, and was not interrupted by any intron. The deduced amino acid sequence of the beta- amylase gene had 42% similarity to the beta-amylase of Arabidopsis thaliana . The beta-amylase gene was expressed in Sacc. cerevisiae and its product w as secreted into the culture medium.