Trichoderma reesei Dehydrogenase, a Pyrroloquinoline Quinone-Dependent Member of Auxiliary Activity Family 12 of the Carbohydrate-Active Enzymes Database: Functional and Structural Characterization

Abstract

Pyrroloquinoline quinone (PQQ) is an important cofactor synthesized by prokaryotes and involved in enzymatic alcohol and sugar oxidation. In eukaryotes, the benefit of PQQ as a vitamin has been suggested but never proved. Recently, the first eukaryotic enzyme using PQQ was characterized in the basidiomycete Coprinopsis cinerea , demonstrating that fungi are able to use PQQ as an enzyme cofactor. This discovery led to the classification of the fungal PQQ-dependent enzymes in auxiliary activity family 12 (AA12) of the Carbohydrate-Active Enzymes (CAZy) database ( www.cazy.org ) classification. In the present paper, we report on the characterization of the ascomycete AA12 enzyme from Trichoderma reesei ( Tr AA12). Our enzymatic and phylogenetic results show divergence with the only other member of the family characterized, that from the basidiomycete Coprinopsis cinerea . The crystallographic structure of Tr AA12 shows similarities to the global active-site architecture of bacterial glucose dehydrogenases, suggesting a common evolution between the two families.