Ammonia monooxygenase-mediated transformation of 17a-ethinylestradiol: Underlying molecular mechanism

17 & alpha;-ethinylestradiol (EE2) has received increasing attention as an emerging and difficult-to-remove emerging contaminant in recent years. Ammonia-oxidizing bacteria (AOB) have been reported to be effective in EE2 removal, and ammonia monooxygenase (AMO) is considered as the primary enzyme for EE2 removal. However, the molecular mechanism underlying the transformation of EE2 by AOB and AMO is still unclear. This study investigated the molecular mechanism of EE2 degradation using a combination of experimental and computational simulation methods. The results revealed that ammonia nitrogen was essential for the co-metabolism of EE2 by AOB, and that NH3 bound with CuC (one active site of AMO) to induce a conformational change in AMO, allowing EE2 to bind with the other active site (CuB), and then EE2 underwent biological transformation. These results provide a theoretical basis and a novel research perspective on the removal of ammonia nitrogen and emerging contaminants (e.g., EE2) in wastewater treatment.

Automated summary

This study investigates the molecular mechanism of EE2 degradation by AOB and AMO using a combination of experimental and computational simulation methods. The results reveal that ammonia nitrogen is essential for the co-metabolism of EE2 by AOB, and NH3 binds with CuC to induce a conformational change in AMO, enabling EE2 to bind with CuB and undergo biological transformation. These findings provide a theoretical basis and a novel research perspective on the removal of ammonia nitrogen and emerging contaminants in wastewater treatment.