Radu Silaghi-Dumitrescu
Affiliation
Department of Chemistry, Babes-Bolyai University, 11 Arany Janos Street, 400028 Cluj-Napoca, Romania - Research
Do you even own a proton? Awkward spectroscopic quirks with reactivity implications for hemoprotein ferryls
Abstract
The structure and reactivity of biological ferryl centers generally entails three coordinates: (1) the highly-covalent and electronically-robust S=1 double-bonded Fe(IV)-oxo unit, (2) its occasional magnetic coupling and ensuing illuminating particularities such as the two-state reactivity (TSR), and (3) its protonation in hemoproteins where the axial ligand is an anionic cysteine thiolate or tyrosine phenolate. Occasional x-ray diffraction and spectroscopy reports explore situations where exceptions or additions to these coordinates can be argued. Among these are some unusually long iron-oxygen distances in some ferryl crystal structures of histidine-ligated heme proteins, and some accompanying spectroscopy data that raises the intriguing question of whether two ferryl systems with differing Fe-O distances can have (near?)-identical properties when probed spectroscopically. We discuss here such experimental data and explore the topic using, DFT, TD-DFT, QM/MM and ab initio dynamics in conjunction with new experimental data where in some cases exceptions to the three rules/coordinates can be argued, including excited-state chemistry. Case studies in heme peroxidases, globins, and chlorite dismutase are presented (1–5)
References
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- S.-R. Cosma, D. Gorgan, A. M. V. Brânzanic and R. Silaghi-Dumitrescu, J. Inorg. Biochem., 2026, 280, 113312.
- S. Richter, P. Lönnecke, D. Bovan, N. Andrian, B. Stoean, M. Lehene, R. Silaghi-Dumitrescu, L. Gaina, S. Mijatović, D. Maksimović-Ivanić, G. N. N. Kaluđerović and E. Hey-Hawkins, Dalt. Trans., 2025, 54, 3597–3609.
- R. Doukeh, M. Lehene, C. Zagrean-Tuza, A. C. Mot, R. Silaghi-Dumitrescu, C. Sarosi, C. I. Fort, G. L. Turdean, M. Pandele, G. Borodi and L. D. Movileanu, J. Phys. Chem. C, 2025, 129, 20517–20533.
- M. Lehene, C. Zagrean-Tuza, S. D. Iancu, S.-R. Cosma, A. M. V Brânzanic, R. Silaghi-Dumitrescu and B. Stoean, JBIC J. Biol. Inorg. Chem., 2025, 30, 25–34.