New insights on the features of the vinyl phenol reductase from the wine-spoilage yeast Dekkera/Brettanomyces bruxellensis

Vinyl phenol reductase activity was assayed in extracts from 19 strains of Dekkera bruxellensis isolated from wine. In all strains, vinyl phenol reductase activity was insensitive to the presence/absence of 4-vinyl guaiacol, confirming that expression is not related to the presence of the substrate. D. bruxellensis CBS 4481 showed the highest vinyl phenol reductase activity toward 4-vinyl guaiacol. Vinyl phenol reductase from D. bruxellensis CBS 4481 was purified to mass spectrometric homogeneity, and sequenced by trypsinolysis and mass spectrometry. The sequence of the purified protein showed convincing homology with a Cu/Zn superoxide dismutase in the D. bruxellensis AWRI 1499 genome, and indeed it was found to possess both vinyl phenol reductase and superoxide dismutase activities. A bioinformatics analysis of the sequence of vinyl phenol reductase/superoxide dismutase from D. bruxellensis CBS 4481 reveals the presence in this protein of cofactor-binding structural features, that are absent in sequences of superoxide dismutases from related microorganisms, that do not display vinyl phenol reductase activity.