FIGURE 11.

Proposed reaction mechanism of hydroxylamine oxidation to NO by kustc1061. The model, based on the NeHAO mechanism (57), shows the binding of hydroxylamine (H₂N-OH) to the water-bound resting state (upper left), followed by subsequent oxidation of the substrate and removal of the protons that proceed through the {FeNO}⁷ and {FeNO}⁶ nitrosyl states. The model takes into account experimentally established (58, 59) and theoretically predicted (57) reaction intermediates in N-converting ferrihemoproteins, which includes the {FeNO}⁷ nitrosyl species observed in the present study.