Dioxygen activation at non-heme diiron centers: oxidation of a proximal residue in the I100W variant of toluene/o-xylene monooxygenase hydroxylase

The X-ray crystal structure of the I100W variant of ToMOH enzyme and the reaction between diiron(II) and dioxygen which yields a diiron(III) intermediate is described. The intermediate subsequently abstracts an electron from W100 to form a chromophoric mixed-valent diiron(III,IV)-W* species.