One of the most convincing mechanisms to explain how certain migratory species perceive the Earth's magnetic field for orientation involves spin dynamics associated with chemical radicals localized within proteins called cryptochromes [Zadeh-Haghighi2022]. The modulation of spin state interconversion by the magnetic field allows the orientation of the radicals relative to the field lines to be probed, providing a signal that can be amplified to help the animal navigate.

Following studies on the photo-induced radical generation mechanisms in cryptochromes and photolyases [Cailliez2017], we initiated a collaboration with Daniel Kattnig (University of Exeter, thesis of J. Deviers 2023) to investigate the magnetic aspects of the mechanism. We explored an original mechanism involving three radicals, including the superoxide anion (O₂^•-) [Deviers2022a, Deviers2022b]. One notable finding was the identification of several binding sites for this anion on the protein. Compared to the Cl- anion, it appears that the protein can preferentially immobilize O₂^•- at various sites. The residence time and reorientation time of the superoxide at these sites are also consistent with the role of O₂^•- in magnetoreception mechanisms [Deviers2023].