5l6f
From Proteopedia
Xylooligosaccharide oxidase from Myceliophthora thermophila C1 in complex with Xylobiose
Structural highlights
FunctionXYLO_MYCTT Catalyzes the selective oxidation of C1 hydroxyl moieties on mono-, oligo- and polysaccharides with concomitant reduction of molecular oxygen to hydrogen peroxide. This results in the formation of the corresponding lactones, which typically undergo spontaneous hydrolysis. Xylooligosaccharide oxidase is able to oxidize a variety of substrates including D-xylose, D-cellobiose, lactose and arabinose. The enzyme acts primarily on xylooligosaccharides, indicating that it prefers pentose-based oligosaccharides over hexose-based oligosaccharides.[1] Publication Abstract from PubMedBy inspection of the predicted proteome of the fungus Myceliophthora thermophila C1 for VAO-type flavoprotein oxidases, a putative oligosaccharide oxidase was identified. By homologous expression and subsequent purification the respective protein could be obtained. The protein was found to contain a bicovalently bound FAD cofactor. By screening a large number of carbohydrates, several mono- and oligosaccharides could be identified as substrate. The enzyme exhibits a strong substrate preference towards xylooligosaccharides, hence it is named xylooligosaccharide oxidase (XylO). Chemical analyses of the product formed upon oxidation of xylobiose revealed that the oxidation occurs at C1, yielding xylobionate as product. By elucidation of several XylO crystal structures (in complex with a substrate mimic, xylose and xylobiose), the residues that tune the unique substrate specificity and regioselectivity could be identified. The discovery of this novel oligosaccharide oxidase reveals that the VAO-type flavoprotein family harbors oxidases tuned for specific oligosaccharides. The unique substrate profile of XylO hints to a role in the degradation of xylan derived oligosaccharides by the fungus M. thermophila C1. Discovery of a xylooligosaccharide oxidase from Myceliophthora thermophila C1.,Ferrari AR, Rozeboom HJ, Dobruchowska JM, van Leeuwen SS, Vugts AS, Koetsier MJ, Visser J, Fraaije MW J Biol Chem. 2016 Sep 14. pii: jbc.M116.741173. PMID:27629413[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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