Synthesis of derivatized chitooligomers using transglycosidases engineered from the fungal GH20 β-N-acetylhexosaminidase

Article abstract of DOI:10.1002/adsc.201500075

Abstract The synthesis of oligosaccharides using mutant glycosidases has been dynamically developing due to the need for novel carbohydrate-based materials. Chitooligomers (β-1→4-linked oligomers of N-acetylglucosamine) are bioactive compounds applicable in many industrial and pharmacological areas; however, their accessibility is still rather low. In this work, GH20 β-N-acetylhexosaminidase from the fungus Talaromyces flavus was engineered by site-directed mutagenesis to obtain three efficiently transglycosylating variants with ca. 200-times suppressed hydrolytic activity. Thus, we have prepared the first GH20 transglycosidases. In the reactions catalyzed by these mutant β-N-acetylhexosaminidases we were able to easily prepare and isolate both natural and modified chitooligomers in sufficient amounts for their complete spectral characterization and possible further application. The presented method for the synthesis of chitooligomers with aglycones suitable for linking to other biological structures is simple and robust enough to be easily scaled up.