A novel alpha-D-galactosynthase from Thermotoga maritima converts beta-D-galactopyranosyl azide to alpha-galacto-oligosaccharides.
Cobucci-Ponzano, Beatrice ; Zorzetti, Carmela ; Strazzulli, Andrea ; et al. ; - ASI Sponsor
Apr - 2011
ISSN : 1460-2423 ;
journal : Glycobiology

Issue : 4
type: Article Journal

The large-scale production of oligosaccharides is a daunting task, hampering the study of the role of glycans in vivo and the testing of the efficacy of novel glycan-based drugs. Glycosynthases, mutated glycosidases that synthesize oligosaccharides in high yields, are becoming important chemo-enzymatic tools for the production of oligosaccharides. However, while \beta-glycosynthase can be produced with a rather well-established technology, examples of \alpha-glycosynthases are thus far limited only to enzymes from glycoside hydrolase 29 (GH29), GH31 and GH95 families. \alpha-L-Fucosynthases from GH29 use convenient glycosyl azide derivatives as a strategic alternative to glycosyl fluoride donors. However, the general applicability of this method to other \alpha-glycosynthases is not trivial and remains to be confirmed. Here, \beta-D-galactopyranosyl azide was converted to \alpha-galacto-oligosaccharides with good yields and high regioselectivity, catalyzed by a novel \alpha-galactosynthase based on the GH36 \alpha-galactosidase from the hyperthermophilic bacterium Thermotoga maritima. These results open a new avenue to the practical synthesis of biologically interesting \alpha-galacto-oligosaccharides and demonstrate more widespread use of \beta-glycosyl-azide as donors, confirming their utility to expand the repertoire of glycosynthases.

keywords : ASI - Sponsor,Aspartic Acid,Aspartic Acid: chemistry,Azides,Azides: chemistry,Chromatography,Disaccharides,Disaccharides: biosynthesis,Galactose,Galactose: metabolism,Glycine,Glycine: chemistry,Kinetics,Mutagenesis,Mutant Proteins,Mutant Proteins: chemistry,Mutant Proteins: genetics,Mutant Proteins: metabolism,Protein Engineering,Site-Directed,Thermotoga maritima,Thermotoga maritima: enzymology,Thin Layer,alpha-Galactosidase,alpha-Galactosidase: chemistry,alpha-Galactosidase: genetics,alpha-Galactosidase: metabolism