Structure–function characterization reveals new catalytic diversity in the galactose oxidase and glyoxal oxidase family

• Published in: Nature communications 2015-12, Vol.6 (1), p.10197-10197, Article 10197
• Main Authors: Yin, DeLu (Tyler), Urresti, Saioa, Lafond, Mickael, Johnston, Esther M., Derikvand, Fatemeh, Ciano, Luisa, Berrin, Jean-Guy, Henrissat, Bernard, Walton, Paul H., Davies, Gideon J., Brumer, Harry
• Format: Article
• Language: English
• Subjects: 140/131; 38; 42; 631/326/193; 631/45/173; 631/45/603; 64; 82; 82/16; 82/29; 82/83; Alcohol; Alcohol Oxidoreductases - chemistry; Alcohol Oxidoreductases - metabolism; Alcohols; Alcohols - metabolism; Aliphatic alcohols; Aliphatic compounds; Biodiversity; Carbohydrates; Catalysis; Catalytic Domain; Classification; Colletotrichum; Crystallization; Crystallography; Crystallography, X-Ray; Electron Spin Resonance Spectroscopy; Enzymes; Fungal Proteins - chemistry; Fungal Proteins - metabolism; Fusarium; Fusarium graminearum; Galactose; Galactose oxidase; Galactose Oxidase - chemistry; Galactose Oxidase - metabolism; Galactosides; Homology; Humanities and Social Sciences; Hydrogen peroxide; Life Sciences; multidisciplinary; Mutagenesis, Site-Directed; Oxidase; Oxidation; Phylogeny; Phytopathogenic fungi; Pichia; Prospecting; Protein Structure, Secondary; Protein Structure, Tertiary; Proton Magnetic Resonance Spectroscopy; Recombinant Proteins; Science; Science (multidisciplinary); Spectroscopy; Structural analysis; Structure-function relationships
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms10197

Alcohol oxidases, including carbohydrate oxidases, have a long history of research that has generated fundamental biological understanding and biotechnological applications. Despite a long history of study, the galactose 6-oxidase/glyoxal oxidase family of mononuclear copper-radical oxidases, Auxiliary Activity Family 5 (AA5), is currently represented by only very few characterized members. Here we report the recombinant production and detailed structure–function analyses of two homologues from the phytopathogenic fungi Colletotrichum graminicola and C. gloeosporioides , Cgr AlcOx and Cgl AlcOx, respectively, to explore the wider biocatalytic potential in AA5. EPR spectroscopy and crystallographic analysis confirm a common active-site structure vis-à-vis the archetypal galactose 6-oxidase from Fusarium graminearum . Strikingly, however, Cgr AlcOx and Cgl AlcOx are essentially incapable of oxidizing galactose and galactosides, but instead efficiently catalyse the oxidation of diverse aliphatic alcohols. The results highlight the significant potential of prospecting the evolutionary diversity of AA5 to reveal novel enzyme specificities, thereby informing both biology and applications. Auxilliary Activity Family 5 (AA5) comprises mononuclear copper radical oxidases with catalytic diversity that is not well characterised. Here, structural, phylogenetic and biochemical analyses advance our understanding of the potential biological and biotechnology functions of these proteins.