Alpha-zearalenol belongs to the family of Macrolides and Analogues. These are organic compounds containing a lactone ring of at least twelve members. The term 'macrolide' encompasses a diverse family of unrelated compounds with large macrolactam rings. Zearalenol derivative of zearalenone. The mycotoxin zearalenone has been contaminating maize and other grains. It can be hydrolyzed and inactivated by the lactonase ZHD. Zearalenone differs from other quorum-sensing lactones
7 structures(e.g. : 5XO7, 5Z7J, 5IE4... more)(less)5XO7: Crystal structure of a novel ZEN lactonase mutant S105A /alpha-ZOL, 5Z7J: Crystal structure of a novel ZEN lactonase double mutant S105A/Y160A /alpha-ZOL, 5IE4: Crystal structure of a lactonase mutant in complex with substrate a, 5IE5: Crystal structure of a lactonase double mutant in complex with substrate a, 6JR2: Crystal structure of the mycoestrogen-detoxifying lactonase ZHD. ZHD/H242A complex with alpha-ZOL from Clonostachys rosea, 6JRA: Crystal structure of the mycoestrogen-detoxifying lactonase ZHD. ZHD/W183F complex with alpha-ZOL from Clonostachys rosea, 6JRC: Crystal structure of the mycoestrogen-detoxifying lactonase ZHD. ZHD complex with alpha-ZOL from Clonostachys rosea
Title: The Trp183 is essential in lactonohydrolase ZHD detoxifying zearalenone and zearalenols Zhou H, Li L, Zhan B, Wang S, Li J, Hu XJ Ref: Biochemical & Biophysical Research Communications, 522:986, 2020 : PubMed
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.
The enzyme ZHD101 from Clonostachys rosea hydrolyzes and deactivates the mycotoxin zearalenone (ZEN) and its zearalenol (ZOL) derivatives. ZHD101 prefers ZEN to ZOL as its substrate, but ZOL, especially the -form, shows higher estrogenic toxicity than ZEN. To enhance alpha-ZOL selectivity, we solved the complex structures of ZHD101 with both ZOLs and modified several lactone-surrounding residues. Among the mutants, V153H maintained activity for ZEN but showed a 3.7-fold increase in specific activity against alpha-ZOL, with an 2.7-fold reduction in substrate affinity but a 5.2-fold higher turnover rate. We then determined two V153H/ZOL complex structures. Here, the alpha-ZOL lactone ring is hydrogen-bonded to the H153 side chain, yielding a larger space for H242 to reconstitute the catalytic triad. In conclusion, structure-based engineering was successfully employed to improve the ZHD101 activity toward the more toxic alpha-ZOL, with great potential in further industrial applications.
