  1.13.11.78 | (2-amino-1-hydroxyethyl)phosphonate + O2 = glycine + phosphate |
PhnZ oxidatively cleaves the highly stable C-P bond in Pn to produce phosphate. Quantum mechanics/molecular mechanics (QM/MM) calculations reveal that the mechanism of PhnZ consists of four consecutive steps: (1) rate-limiting alpha-H abstraction of Pn by FeIII-superoxo, (2) formation of FeIIIOOCalpha peroxide, (3) concerted O insertion into Calpha-P bond of organophosphonate initiated by inverse heterolytic O-O cleavage, and (4) phosphonate hydrolysis to glycine and phosphate. Inverse heterolytic O-O cleavage of FeIIIOOCalpha intermediate renders the distal O atom more oxidative to oxygenate organophosphonate than the homolytic O-O cleavage. The unusual inverse heterolytic O-O cleavage mode constitutes a third iron-mediated O-O activation scenario in nature, which is expected to have its broad occurrence in oxidative transformation involving heteroatoms of sulfur and phosphorus, possible enzymatic O-O cleavage mechanisms from FeIII/IIOOR(H) intermediates, and electronic structure of resting state and superoxo intermediates, overview |
743907 |
| 1.13.11.78 | (2-amino-1-hydroxyethyl)phosphonate + O2 = glycine + phosphate |
the enzyme uses a diiron oxygenase mechanism for catabolism of organophosphonates. The fifth histidine that is conserved in the PhnZ subclade, H62, specifically interacts with the substrate 1-hydroxy, residue Y24 forms a transient ligand interaction at the dioxygen binding site of Fe2+. Residues Y24 and E27 mediate a unique induced-fit mechanism whereby E27 specifically recognizes the 2-amino group of the bound substrate and toggles the release of Y24 from the active site, thereby creating space for molecular oxygen to bind to the second Fe2+. The 2-amino group of (R)-2 triggers an induced-fit mechanism |
743680 |
