The structure of a complex of the lactonohydrolase zearalenone hydrolase with the hydrolysis product of zearalenone at 1.60   Å resolution

Zearalenone hydrolase (ZHD) is an α / β -hydrolase that detoxifies and degrades the lactone zearalenone (ZEN), a naturally occurring oestrogenic mycotoxin that contaminates crops. Several apoenzyme and enzyme – substrate complex structures have been reported in the resolution range 2.4 – 2.6   Å . However, the properties and mechanism of this enzyme are not yet fully understood. Here, a 1.60   Å resolution structure of a ZHD – product complex is reported which was determined from a C-terminally His6-tagged ZHD crystal soaked with 2   mM ZEN for 30   min. It shows that after the lactone-bond cleavage, the phenol-ring region moves closer to residues Leu132, Tyr187 and Pro188, while the lactone-ring region barely moves. Comparisons of the ZHD – substrate and ZHD – product structures show that the hydrophilic interactions change, especially Trp183   N ∊ 1, which shifts from contacting O2 to O12 ′ , suggesting that Trp183 is responsible for the unidirectional translational movement of the phenol ring. This structure provides information on the final stage of the catalytic mechanism of zearalenone hydrolysis.

Source: Acta Crystallographica Section F - June 16, 2017 Category: Biochemistry Authors: Qi, Q. Yang, W.-J. Zhou, H.-J. Ming, D.-M. Sun, K.-L. Xu, T.-Y. Hu, X.-J. Lv, H. Tags: lactonohydrolase Clonostachys rosea zearalenone catalysis mechansim research communications Source Type: research