Wood decay fungi have complex detoxification systems that enable them to cope with secondary metabolites produced by plants. Although the number of genes encoding for glutathione transferases (GSTs) is especially expanded in lignolytic fungi, little is known about their physiological target molecules. In this study, by combining thermal shift assay and affinity crystallography we highlighted interaction between polyphenols and GSTs Omega from the white-rot fungus Trametes versicolor (TvGSTOs). Two distinct ligand-binding sites were found, an open valley at the dimer interface and a deep closed hydrophobic site that corresponds to a peculiar H-site. This site appears to be optimized for aromatic ligand binding, and retains the flavonoid dihydrowogonin from a partially purified wild-cherry extract. Enzymatic inhibition assay and X-ray crystallography confirmed TvGSTOs affinity for polyphenols. The non-catalytic interaction observed suggests that TvGSTOs could be involved in the transport of polyphenols as reported for plant GSTs which have been associated with the transport of anthocyanins into the vacuole.

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