�-galactosidases (EC 3.2.1.23) catalyze the hydrolysis of the �-1,4-D-glycosidic linkage of lactose and structurally related substrates. �-galactosidases have two main biotechnological applications in the food industry - the removal of lactose from milk and dairy products as well as the production of galacto-oligosaccharides (GOS), which have been classified as one of the few proven prebiotics, exploiting the transglycosylation potential of these enzymes.  In this present study, the �-galI gene from Bifidobacterium breve DSM20213, an isolate from infant gut, encoding a �-galactosidase that belongs to glycoside hydrolase family GH2 was cloned and heterologously expressed in Escherichia coli. Subsequently, the recombinant b-galactosidase was purified, characterized and used for the synthesis of GOS. Furthermore, the crystal structure of this homodimeric enzyme was determined at 2.2 � resolution. This is the structure for a �-galactosidase from a human Bifidobacterium isolate to date, which opens new possibilities for comprehensive studies of this enzyme.

Structure of a β-galactosidase (ß-gal I) from <i>Bifidobacterium breve </i>DSM 20213: Cloning, heterologous expression, biochemical characterization, and structural studies

245th National Meeting (2013)

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Structure of a β-galactosidase (ß-gal I) from Bifidobacterium breve DSM 20213: Cloning, heterologous expression, biochemical characterization, and structural studies