Zhou_2020_Biochem.Biophys.Res.Commun_522_986

Lactonohydrolase ZHD can detoxify oestrogenic mycotoxin zearalenone and zearalenols through hydrolysis and decarboxylation. The detail mechanism, especially the role of Trp183, which interacts with substrate through p-pi interaction and one hydrogen bond, is still unknown. The Trp183 mutants abolished activity to ZEN, alpha-ZOL and beta-ZOL, except that W183F mutant retained about 40% activity against alpha-ZOL. In two W183F-reactant complex structures the reactants still bind at the active position and it suggested that this p-pi interaction takes responsible for the reactants recognization and allocation. Further, the ZHD-productant complex structures showed that the resorcinol ring of hydrolysed alpha-ZOL and hydrolysed beta-ZOL move a distance of one ring as compare to the resorcinol ring of reactant alpha-ZOL and beta-ZOL. The same movement also found in comparison of hydrolysed ZEN and ZEN. In the structure of W183F complex with hydrolysed alpha-ZOL the resorcinol ring of hydrolysed alpha-ZOL doesn't move as compare to the resorcinol ring of reactant alpha-ZOL. It suggested the Trp183 coordinated hydrogen bond takes responsible for the movement of the hydrolysed product. These functional and structural results suggested that Trp183 is essential for ZHD detoxifying zearalenone and zearalenols.