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Updated: Jun 14, 2026

Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Fe-heme structure in Cu, Zn superoxide dismutase from Haemophilus ducreyi by X-ray absorption spectroscopy
Paola D'Angelo1, Andrea Zitolo, Francesca Pacello
1Department of Chemistry University "La Sapienza", Rome, Italy. p.dangelo@caspur.it <p.dangelo@caspur.it>
Abstract:
We have carried out an X-ray Absorption Spectroscopy (XAS) study of ferric, ferrous, CO- and NO-bound Haemophilus ducreyi Cu,ZnSOD (HdSOD) in solution to investigate the structural modifications induced by the binding of small gaseous ligands to heme in this enzyme. The combined analysis of EXAFS and XANES data has allowed us to characterize the local structure around the Fe-heme with 0.02A accuracy, revealing a heterogeneity in the distances between iron and the two histidine ligands which was not evident in the X-ray crystal structure. In addition, we have shown that the metal oxidation state does not influence the Fe-heme coordination environment, whereas the presence of the CO and NO ligands induces local structural rearrangements in the enzyme which are very similar to those already observed in other hexa-coordinated heme proteins, such as neuroglobin.
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