A gene encoding Achlya bisexualis beta-amylase and its expression in Saccharomyces cerevisiae

Part of a beta -amylase genomic DNA sequence from the oomycete, Achlya bise xualis was cloned by polymerase chain reaction (PCR) using degenerate oligo nucleotide primers derived from the conserved regions of other known beta - amylase sequences. The 5'- and 3'-regions of the beta -amylase gene were am plified by genome walking method. The Ach. bisexualis beta -amylase gene co nsisted of a 1338 bp open reading frame, encoding a protein of 446 amino ac ids with a molecular weight of 49 381 Da, and was not interrupted by any in tron. The deduced amino acid sequence of the beta -amylase gene had 67% sim ilarity to the beta -amylase of Saprolegnia ferax, followed by 40% similari ty to that of Arabidopsis thaliana. The beta -amylase gene was expressed in Saccharomyces cerevisiae placing it under the control of the alcohol dehyd rogenase gene (ADC1) promoter.