Can ferric-oxyl excited states explain elongated iron-oxygen bonds in heme peroxidase catalytic intermediates?
The use of X-ray structures to determine and interpret the ferryl iron-oxygen bond order in molecular oxygen-activating heme enzymes has, in the past, been controversial. This has mainly stemmed from the susceptibility of ferryl species to X-ray-induced electronic state changes. In this work we establishe using time-resolved serial femtosecond X-ray crystallography (tr-SFX) on a dye-decolourising peroxidase that the ferryl intermediate species (Compounds I and II) captured following in situ mixing of microcrystals with H<sub>2</sub>O<sub>2</sub> have single, rather than the double bond character expected. X-ray emission validated tr-SFX data with quantum refinement, time-dependent-DFT calculations and QM/MM geometry optimizations together support the concept that the single iron-oxygen bond character is not an indication of ferryl reduction or a protonated form (Fe<sup>IV</sup>-OH) but is instead attributed to the existence of accessible excited states possessing ferric-oxyl (Fe<sup>III</sup>-O<sup>•-</sup>) character. Such states offer insight into the nature of ferryl heme.
Authors
- Tiankun Zhou (ORCID: https://orcid.org/0000-0002-6116-7483)
- Aaron S. Brewster (ORCID: https://orcid.org/0000-0002-0908-7822)
- Hiroki Makita (ORCID: https://orcid.org/0000-0002-4968-914X)
- Allen Milster Orville (ORCID: https://orcid.org/0000-0002-7803-1777)
- Ulf Ryde (ORCID: https://orcid.org/0000-0001-7653-8489)
- Margaret Doyle (ORCID: https://orcid.org/0000-0002-7289-3544)
- Maria Lehene (ORCID: https://orcid.org/0000-0003-0768-2342)
- Pierre Aller (ORCID: https://orcid.org/0000-0002-1793-7030)
- Juan Sánchez-Weatherby (ORCID: https://orcid.org/0000-0001-5893-9641)
- Vittal K. Yachandra (ORCID: https://orcid.org/0000-0002-3983-7858)
- Marina Lučić (ORCID: https://orcid.org/0000-0002-8264-8251)
- Adrian M. V. Branzanic
- Kuntal Chatterjee (ORCID: https://orcid.org/0000-0001-6984-5026)
- Kristina Lundgren (ORCID: https://orcid.org/0009-0002-2611-7883)
- Sandra Mous (ORCID: https://orcid.org/0000-0002-3532-5978)
- Philipp S. Simon (ORCID: https://orcid.org/0000-0002-2859-4475)
- L.J. Williams (ORCID: https://orcid.org/0009-0002-4066-3899)
- Radu L. Silaghi-Dumitrescu
- Jan Kern
- Sebastian Dehe
- Junko Yano
- Jos J.A.G. Kamps
- Leland Gee
- Michael T. Wilson
- Jonathan A. R. Worrall
- Michael A. Hough
- Amy J. Thompson
Institutions
- University of Essex (GB)
- Lawrence Berkeley National Laboratory (US)
- Lund University (SE)
- SLAC National Accelerator Laboratory (US)
- Diamond Light Source (GB)
- Babeș-Bolyai University (RO)
- Research Complex at Harwell (GB)
- Swedish e-Science Research Centre (SE)
- Linac Coherent Light Source (US)
Publication Details
- Journal
- Nature Communications
- Published
- 2026-02-03
- DOI
- https://doi.org/10.1038/s41467-026-69192-8
- Primary Topic
- Enzyme-mediated dye degradation
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- U.S. Department of Energy
- University of Essex
- Wellcome Trust
- Diamond Light Source
- European Commission
- European Synchrotron Radiation Facility
- Lunds Universitet
- Vetenskapsrådet
- National Institutes of Health
- Office of Science
- Biotechnology and Biological Sciences Research Council
- Basic Energy Sciences
- Chemical Sciences, Geosciences, and Biosciences Division
- SLAC National Accelerator Laboratory