Neuroglobin Provides a Convenient Scaffold to Investigate the Triplet-State Properties of Porphyrins by Time-Resolved EPR Spectroscopy and Magnetophotoselection

0559969 - BC 2023 RIV DE eng J - Journal Article
Ciuti, S. - Barbon, A. - Bortolus, M. - Agostini, Alessandro - Bergantino, E. - Martin, C. - Di Valentin, M. - Carbonera, D.
Neuroglobin Provides a Convenient Scaffold to Investigate the Triplet-State Properties of Porphyrins by Time-Resolved EPR Spectroscopy and Magnetophotoselection.
Applied Magnetic Resonance. Roč. 53, č. 7-9 (2022), s. 1031-1042. ISSN 0937-9347. E-ISSN 1613-7507
R&D Projects: GA MŠMT(CZ) EF18_053/0016982
Institutional support: RVO:60077344
Keywords : Absorption spectroscopy * Chromophores * Magnetophotoselection * Porphyrins * Proteins
OECD category: Biophysics
Impact factor: 1, year: 2022
Method of publishing: Open access
https://link.springer.com/article/10.1007/s00723-021-01421-3

The photo-excited triplet state of Zn-protoporphyrin IX located in the heme pocket of human neuroglobin has been investigated by time-resolved EPR coupled to magnetophotoselection. The triplet state in the protein matrix has been compared with the model complex in organic glass, considering both non-coordinating and coordinating solvent mixtures. The protein matrix plays an important role in stabilizing the coordination of the embedded chromophore, resulting in a more homogeneous environment relative to that of the chromophore in a glassy solvent, even in the presence of an axial nitrogenous ligand like pyridine. The EPR spectral parameters point out a slow Jahn-Teller interconversion between slightly different triplet states, both in organic solvent and in the protein matrix. The EPR-magnetophotoselection allows us to propose a reinterpretation of the assignment of the Q bands in the electronic absorption spectrum.
Permanent Link: https://hdl.handle.net/11104/0340241