Construction of an alpha-amylase/glucoamylase fusion gene and its expression in Saccharomyces cerevisiae. |
| |
| Authors: | I Shibuya G Tamura H Shima T Ishikawa S Hara |
| |
| Institution: | Research Institute of Brewing Resources Co., Ltd., Tokyo, Japan. |
| |
| Abstract: | A fusion gene which encoded a polypeptide comprised of 1116 amino acids was constructed using the alpha-amylase and glucoamylase cDNAs of Aspergillus shirousamii. When the fusion gene was expressed in Saccharomyces cerevisiae using a yeast expression plasmid under the control of the yeast ADH1 promoter, a bifunctional fusion protein (145 kDa) having both alpha-amylase and glucoamylase activities was secreted into the culture medium. The fusion protein had higher raw-starch-digesting activity than those of the original alpha-amylase and glucoamylase, and adsorbed onto raw starch like the glucoamylase. It was suggested that the characteristics are a result of the raw-starch-affinity site in the glucoamylase domain of the fusion protein. |
| |
| Keywords: | |
|
|
