Copper radical oxidases (CROs) are redox enzymes able to oxidize alcohols or aldehydes, while only requiring a single copper atom as cofactor. Studied CROs are found in one of two subfamilies within the Auxiliary Activities family 5 (AA5) in the carbohydrate-active enzymes database. We here characterize an AA5 enzyme outside the subfamily classification from the opportunistic bacterial pathogen Burkholderia pseudomallei, which curiously was fused to a carbohydrate esterase family 3 domain. The enzyme was shown to be a promiscuous primary alcohol oxidase, with an activity profile similar to enzymes from subfamily 2. The esterase domain was inactive on all tested substrates, and structural predictions revealed this being an effect of crippling substitutions in the expected active site residues.
Keywords: Burkholderia; Auxiliary Activity family 5; alcohol oxidase; copper-radical oxidase; multidomain enzyme.
© 2023 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.