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The pH-Induced Selectivity Between Cysteine or Histidine Coordinated Heme in an Artificial alpha-Helical Metalloprotein

Abstract : De Novo metalloprotein design assesses the relationship between metal active site architecture and catalytic reactivity. Herein, we use an alpha-helical scaffold to control the iron coordination geometry when a heme cofactor is allowed to bind to either histidine or cysteine ligands, within a single artificial protein. Consequently, we uncovered a reversible pH-induced switch of the heme axial ligation within this simplified scaffold. Characterization of the specific heme coordination modes was done by using UV-Vis and Electron Paramagnetic Resonance spectroscopies. The penta- or hexa-coordinate thiolate heme (9 ≤ pH ≤ 11) and the penta-coordinate imidazole heme (6 ≤ pH ≤ 8.5) reproduces well the heme ligation in chloroperoxidases or cyt P450 monooxygenases and peroxidases, respectively. The stability of heme coordination upon ferric/ferrous redox cycling is a crucial property of the construct. At basic pHs, the thiolate mini-heme protein can catalyze O2 reduction when adsorbed onto a pyrolytic graphite electrode.
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https://hal.archives-ouvertes.fr/hal-03017501
Contributor : Anabella Ivancich Connect in order to contact the contributor
Submitted on : Monday, October 18, 2021 - 2:14:10 PM
Last modification on : Tuesday, November 2, 2021 - 12:43:17 PM

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Karl Koebke, Toni Kühl, Elisabeth Lojou, Borries Demeler, Barbara Schoepp-Cothenet, et al.. The pH-Induced Selectivity Between Cysteine or Histidine Coordinated Heme in an Artificial alpha-Helical Metalloprotein. Angewandte Chemie International Edition, Wiley-VCH Verlag, 2021, 60 (8), pp.3974-3978. ⟨10.1002/anie.202012673⟩. ⟨hal-03017501v3⟩

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