Fungal PQQ-dependent dehydrogenases and their potential in biocatalysis.

Highlights • The first eukaryotic PQQ-dependent dehydrogenase was discovered in a plant saprophytic fungus. • This multi-domain enzyme, Cc PDH, defines a new family of PQQ-dependent eukaryotic enzymes. • Cc PDH oxidizes 2-keto- d -glucose, l -fucose, and rare pyranoses, such as d -arabinose and l -galactose. • The dehydrogenase domain of Cc PDH is the founding member of family AA12 in CAZy. • Cc PDH can activate on LPMOs. In 2014, the first fungal pyrroloquinoline-quinone (PQQ)-dependent enzyme was discovered as a pyranose dehydrogenase from the basidiomycete Coprinopsis cinerea (Cc PDH). This discovery laid the foundation for a new Auxiliary Activities (AA) family, AA12, in the Carbohydrate-Active enZymes (CAZy) database and revealed a novel enzymatic activity potentially involved in biomass conversion. This review summarizes recent progress made in research on this fungal oxidoreductase and related enzymes. Cc PDH consists of the catalytic PQQ-binding AA12 domain, an N-terminal cytochrome b AA8 domain, and a C-terminal family 1 carbohydrate-binding module (CBM1). Cc PDH oxidizes 2-keto- d -glucose (d -glucosone), l -fucose, and rare sugars such as d -arabinose and l -galactose, and can activate lytic polysaccharide monooxygenases (LPMOs). Bioinformatic studies suggest a widespread occurrence of quinoproteins in eukaryotes as well as prokaryotes. [ABSTRACT FROM AUTHOR]