Metalloproteins utilize O2 as an oxidant, and they often achieve a 4-electron reduction without H2O2 or oxygen radical release. Several proteins have been designed to catalyze one or two-electron oxidative chemistry, but the de novo design of a protein that catalyzes the net 4-electron reduction of O2 has not been reported yet. We report the construction of a diiron-binding four-helix bundle, made up of two different covalently linked a2 monomers, through click chemistry. Surprisingly, the prototype protein, DF-C1, showed a large divergence in its reactivity from earlier DFs (DF: due ferri, two iron). DFs release the quinone imine and free H2O2 in the oxidation of 4-aminophenol in the presence of O2, whereas FeIII-DF-C1 sequesters the quinone imine into the active site, and catalyzes inside the scaffold an oxidative coupling between oxidized and reduced 4-aminophenol. The asymmetry of the scaffold allowed a fine-engineering of the substrate binding pocket,that ensures selectivity.

A De Novo Heterodimeric DueFerri Protein Minimizes the Release of Reactive Intermediates in Dioxygen-Dependent Oxidation

Chino, Marco;Leone, Linda;Maglio, Ornella;D'alonzo, Daniele;Pirro, Fabio;Pavone, Vincenzo;Nastri, Flavia;Lombardi, Angela
2017

Abstract

Metalloproteins utilize O2 as an oxidant, and they often achieve a 4-electron reduction without H2O2 or oxygen radical release. Several proteins have been designed to catalyze one or two-electron oxidative chemistry, but the de novo design of a protein that catalyzes the net 4-electron reduction of O2 has not been reported yet. We report the construction of a diiron-binding four-helix bundle, made up of two different covalently linked a2 monomers, through click chemistry. Surprisingly, the prototype protein, DF-C1, showed a large divergence in its reactivity from earlier DFs (DF: due ferri, two iron). DFs release the quinone imine and free H2O2 in the oxidation of 4-aminophenol in the presence of O2, whereas FeIII-DF-C1 sequesters the quinone imine into the active site, and catalyzes inside the scaffold an oxidative coupling between oxidized and reduced 4-aminophenol. The asymmetry of the scaffold allowed a fine-engineering of the substrate binding pocket,that ensures selectivity.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/693713
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