The activity of barley alpha-amylase on starch granules is enhanced by fusion of a starch binding domain from Aspergillus niger glucoamylase
Juge, N.; Nøhr, J.; Le Gal-Coëffet, M-Françoise.; Kramhøft, B.; Furniss, C.S.M.; Planchot, Véronique.; Archer, D.B.; Williamson, G.; Svensson, B.
Biochimica et Biophysica Acta 1764(2): 275-284
ISSN/ISBN: 0006-3002 PMID: 16403494 DOI: 10.1016/j.bbapap.2005.11.008
High affinity for starch granules of certain amylolytic enzymes is mediated by a separate starch binding domain (SBD). In Aspergillus niger glucoamylase (GA-I), a 70 amino acid O-glycosylated peptide linker connects SBD with the catalytic domain. A gene was constructed to encode barley alpha-amylase 1 (AMY1) fused C-terminally to this SBD via a 37 residue GA-I linker segment. AMY1-SBD was expressed in A. niger, secreted using the AMY1 signal sequence at 25 mg x L-1 and purified in 50% yield.