Axial Coordination of Carboxylate Activates the Non-heme Fe~IV=O Unit

摘要

High-valent oxoiron intermediates have been implicated in the dioxygen activation mechanisms of many mononuclear non-heme iron enzymes as the oxidizing species in metabol-ically important transformations.Recently,the first such species was directly observed in the catalytic cycle of TauD,a member of the superfamily of enzymes with a common 2-His-1-carboxylate facial triad motif that binds the active-site iron center.This short-lived intermediate has a high-spin iron(IV)center and the Fe-O bond is 1.62 A long(determined by extended X-ray absorption fine structure spectroscopy(EXAFS)).