Characterization of a novel AA3_1 xylooligosaccharide dehydrogenase from Thermothelomyces myriococcoides CBS 398.93

Biotechnology for Biofuels and Bioproducts

Research

Annie Bellemare¹  Thi Truc Minh Nguyen¹  Adrian Tsang¹  Emma Master²  Hongbo Zhao³  Johanna Karppi³  Maija Tenkanen³ 

[1] Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke Street West, H4B 1R6, Montreal, QC, Canada;Department of Bioproducts and Biosystems, Aalto University, Espoo, Finland;Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada;Department of Food and Nutrition, University of Helsinki, Helsinki, Finland;

关键词: Xylooligosaccharide dehydrogenase;    Cellobiose dehydrogenase;    Thermothelomyces myriococcoides;    CAZy AA3;    AA3_1;   

DOI  :  10.1186/s13068-022-02231-w

 received in 2022-09-19, accepted in 2022-11-17,  发布年份 2022

来源: Springer

【 摘 要 】

BackgroundThe Carbohydrate-Active enZymes (CAZy) auxiliary activity family 3 (AA3) comprises flavin adenine dinucleotide-dependent (FAD) oxidoreductases from the glucose–methanol–choline (GMC) family, which play auxiliary roles in lignocellulose conversion. The AA3 subfamily 1 predominantly consists of cellobiose dehydrogenases (CDHs) that typically comprise a dehydrogenase domain, a cytochrome domain, and a carbohydrate-binding module from family 1 (CBM1).ResultsIn this work, an AA3_1 gene from T. myriococcoides CBS 398.93 encoding only a GMC dehydrogenase domain was expressed in Aspergillus niger. Like previously characterized CDHs, this enzyme (TmXdhA) predominantly accepts linear saccharides with β-(1 → 4) linkage and targets the hydroxyl on the reducing anomeric carbon. TmXdhA was distinguished, however, by its preferential activity towards xylooligosaccharides over cellooligosaccharides. Amino acid sequence analysis showed that TmXdhA possesses a glutamine at the substrate-binding site rather than a threonine or serine that occupies this position in previously characterized CDHs, and structural models suggest the glutamine in TmXdhA could facilitate binding to pentose sugars.ConclusionsThe biochemical analysis of TmXdhA revealed a catalytic preference for xylooligosaccharide substrates. The modeled structure of TmXdhA provides a reference for the screening of oxidoreductases targeting xylooligosaccharides. We anticipate TmXdhA to be a good candidate for the conversion of xylooligosaccharides to added-value chemicals by its exceptional catalytic ability.

【 授权许可】

CC BY   
© The Author(s) 2022

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