Bk. Dalmia et al., DOMAIN-E OF BACILLUS-MACERANS CYCLODEXTRIN GLUCANOTRANSFERASE - AN INDEPENDENT STARCH-BINDING DOMAIN, Biotechnology and bioengineering, 47(5), 1995, pp. 575-584
The starch-binding domains of glucoamylase I (SBD of GA-I) from Asperg
illus awamori and of cyclodextrin glucanotransferase (domain E of CGTa
se) from Bacillus macerans were fused to the C-terminus of beta-galact
osidase (beta-gal). The majority of the fusion proteins produced in Es
cherichia coli were found as inclusion bodies. Active fusion proteins
were purified by partial solubilization of the inclusion bodies with 2
M urea followed by affinity chromatography. Adsorption isotherms of p
urified fusion proteins on corn starch and cross-linked amylose were g
enerated. The beta-gal fusion proteins had similar affinities for cros
s-linked amylose and corn starch but significantly different saturatio
n capacities on corn starch. The adsorption and elution data from the
potato starch column as well as the adsorption isotherms of beta-gal-d
omain E fusion protein (BDE109) on corn starch and cross-linked amylos
e demonstrated that domain E of CGTase is an independent domain, which
retained its starch-binding activity when separated from the other fo
ur (A-D) domains in CGTase. (C) 1995 John Wiley & Sons, Inc.