Biochemical Characterization of the Functional Roles of Residues in the Active Site of the β-Galactosidase from Bacillus circulans ATCC 31382.

ABSTRACT: The β-galactosidase enzyme from Bacillus circulans ATCC 31382 BgaD is widely used in the food industry to produce prebiotic galactooligosaccharides (GOS). Recently, the crystal structure of a C-terminally truncated version of the enzyme (BgaD-D) has been elucidated. The roles of active site amino acid residues in β-galactosidase enzyme reaction and product specificity have remained unknown. On the basis of a structural alignment of the β-galactosidase enzymes BgaD-D from B. circulans and BgaA from Streptococcus pneumoniae, and the complex of BgaA with LacNAc, we identified eight active site amino acid residues (Arg185, Asp481, Lys487, Tyr511, Trp570, Trp593, Glu601, and Phe616) in BgaD-D. This study reports an investigation of the functional roles of these residues, using site-directed mut

SUBMITTER: Yin H 

PROVIDER: S-EPMC5481816 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature