title: Discovery of a Xylooligosaccharide Oxidase from Myceliophthora thermophila C1.
abstract: By inspection of the predicted proteome of the fungus Myceliophthora thermophila C1 for vanillyl-alcohol oxidase (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 substrates. The enzyme exhibits a strong substrate preference toward 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 at a role in the degradation of xylan-derived oligosaccharides by the fungus M. thermophila C1.
authors.affiliation: From the Molecular Enzymology Group and.
authors.forename: Alessandro R
authors.initials: AR
authors.lastname: Ferrari
authors.affiliation: From the Molecular Enzymology Group and.
authors.forename: Henriëtte J
authors.initials: HJ
authors.lastname: Rozeboom
authors.affiliation: Microbial Physiology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen.
authors.forename: Justyna M
authors.initials: JM
authors.lastname: Dobruchowska
authors.affiliation: Microbial Physiology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG Groningen.
authors.forename: Sander S
authors.initials: SS
authors.lastname: van Leeuwen
authors.affiliation: Dupont Industrial Biosciences, 6709 PA Wageningen, and.
authors.forename: Aniek S C
authors.initials: AS
authors.lastname: Vugts
authors.affiliation: Dupont Industrial Biosciences, 6709 PA Wageningen, and.
authors.forename: Martijn J
authors.initials: MJ
authors.lastname: Koetsier
authors.affiliation: the Fungal Genetics and Technology Consultancy, 6700 AJ Wageningen, The Netherlands.
authors.forename: Jaap
authors.initials: J
authors.lastname: Visser
authors.affiliation: From the Molecular Enzymology Group and m.w.fraaije@rug.nl.
authors.forename: Marco W
authors.initials: MW
authors.lastname: Fraaije
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D004187:Disaccharides / Q000378:metabolism; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D005965:Glucuronates / Q000378:metabolism*; D008958:Models, Molecular; D009844:Oligosaccharides / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D016415:Sequence Alignment; D020037:Sordariales / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D013379:Substrate Specificity; D014990:Xylans / Q000378:metabolism
chemical_list: D004187:Disaccharides; D005965:Glucuronates; D009844:Oligosaccharides; D014990:Xylans; C570991:xylooligosaccharide; D005182:Flavin-Adenine Dinucleotide; D010088:Oxidoreductases; C004173:xylobiose
keywords: CAZy; carbohydrate; carbohydrate processing; crystal structure; flavin adenine dinucleotide (FAD); oligosaccharide; oxidase; xylan; xylose