Spectroscopic analyses of 2-oxoglutarate-dependent oxygenases: TauD as a case study

Abstract

A wide range of spectroscopic approaches have been used to interrogate the mononuclear iron metallocenter in 2-oxoglutarate (2OG)-dependent oxygenases. The results from these spectroscopic studies have provided valuable insights into the structural changes at the active site during substrate binding and catalysis, thus providing critical information that complements investigations of these enzymes by x-ray crystallography, biochemical, and computational approaches. This mini-review highlights taurine hydroxylase (taurine:2OG dioxygenase, TauD) as a case study to illustrate the wealth of knowledge that can be generated by applying a diverse array of spectroscopic investigations to a single enzyme. In particular, electronic absorption, circular dichroism, magnetic circular dichroism, conventional and pulse electron paramagnetic, Mössbauer, X-ray absorption, and resonance Raman methods have been exploited to uncover the properties of the metal site in TauD.

Visualizing the Reaction Cycle in an Iron(II)- and 2-(Oxo)-glutarate-Dependent Hydroxylase

“…The presence of the alkoxide is somewhat surprising, given the high p K a of the hydroxyl group (~ 17). The observation may, however, be consistent with proposals of initial rebound of the deprotonated oxo unit 28 and could have important implications for bifunctional Fe/2OG enzymes that first hydroxylate their substrates and then effect distinct transformations of the alcohol (or alkoxide) intermediates. 8 …”

Dioxygen Activation and O–O Bond Formation Reactions by Manganese Corroles

“…1 One notable example is the O 2 -activation by iron-containing heme and nonheme enzymes, in which iron–oxygen intermediates have been trapped and characterized using various spectroscopic techniques. 2,3 In biomimetic studies, a large number of iron–oxygen intermediates bearing porphyrin and nonporphyrin ligands have been successfully synthesized as the model compounds of the heme and nonheme iron enzymes, and their chemical properties as well as the mechanisms of the formation of the iron–oxygen intermediates have been elucidated using the model compounds. 4,5 In most of the model studies, artificial oxidants, such as iodosylbenzene (PhIO), peracids, NaOCl, H 2 O 2 , and alkyl hydroperoxides, have been used as surrogates for O 2 for the synthesis of the iron–oxygen intermediates.…”

Achieving One-Electron Oxidation of a Mononuclear Nonheme Iron(V)-Imido Complex

“…14 In biomimetic studies, heme and nonheme iron-oxo complexes have been synthesized, characterized, and investigated in various oxidation reactions over the past several decades. 2,3 Compared to the heme and nonheme iron-oxo species, the chemistry of iron-imido analogs is less clearly understood.…”