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

Delu Tyler Yin (1) , Saioa Urresti (2) , Mickael Lafond (1, 3) , Esther M. Johnston (2) , Jean-Guy Berrin (4)

1 Michael Smith Laboratories and Department of Chemistry
2 Department of Chemistry
3 ISM2 - Institut des Sciences Moléculaires de Marseille
4 BBF - Biodiversité et Biotechnologie Fongiques

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 [i]Colletotrichum graminicola[/i] and [i]C. gloeosporioides[/i],[i] Cgr[/i]AlcOx and [i]Cgl[/i]AlcOx, respectively, to explore the wider biocatalytic potential in AA5. EPR spectroscopy and crystallographic analysis confirm a common active-site structure [i]vis-à-vis[/i] the archetypal galactose 6-oxidase from [i]Fusarium graminearum[/i]. Strikingly, however, [i]Cgr[/i]AlcOx and [i]Cgl[/i]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.

Domaines: Sciences du Vivant [q-bio]

Delu Tyler Yin, Saioa Urresti, Mickael Lafond, Esther M. Johnston, Jean-Guy Berrin. Structure-function characterization reveals new catalytic diversity in the galactose oxidase and glyoxal oxidase family. Nature Communications, 2015, 6, pp.10197. ⟨10.1038/ncomms10197⟩. ⟨hal-01269516⟩