Avian cryptochrome 4 binds superoxide

Flavin-binding cryptochromes are blue-light sensitive photoreceptors that have been implicated with magnetoreception in some species. The photocycle involves an intra-protein photo-reduction of the flavin cofactor, generating a magnetosensitive radical pair, and its subsequent re-oxidation. Superoxi...

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Main Authors: Jean Deviers, Fabien Cailliez, Aurélien de la Lande, Daniel R. Kattnig
Format: Article
Language:English
Published: Elsevier 2024-12-01
Series:Computational and Structural Biotechnology Journal
Online Access:http://www.sciencedirect.com/science/article/pii/S200103702300483X
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author Jean Deviers
Fabien Cailliez
Aurélien de la Lande
Daniel R. Kattnig
author_facet Jean Deviers
Fabien Cailliez
Aurélien de la Lande
Daniel R. Kattnig
author_sort Jean Deviers
collection DOAJ
description Flavin-binding cryptochromes are blue-light sensitive photoreceptors that have been implicated with magnetoreception in some species. The photocycle involves an intra-protein photo-reduction of the flavin cofactor, generating a magnetosensitive radical pair, and its subsequent re-oxidation. Superoxide (O2•−) is generated in the re-oxidation with molecular oxygen. The resulting O2•−-containing radical pairs have also been hypothesised to underpin various magnetosensitive traits, but due to fast spin relaxation when tumbling in solution would require immobilisation. We here describe our insights in the binding of superoxide to cryptochrome 4 from C. livia based on extensive all-atom molecular dynamics studies and density-functional theory calculations. The positively charged “crypt” region that leads to the flavin binding pocket transiently binds O2•− at 5 flexible binding sites centred on arginine residues. Typical binding times amounted to tens of nanoseconds, but exceptional binding events extended to several hundreds of nanoseconds and slowed the rotational diffusion, thereby realising rotational correlation times as large as 1 ns. The binding sites are particularly efficient in scavenging superoxide escaping from a putative generation site close to the flavin-cofactor, possibly implying a functional relevance. We discuss our findings in view of a potential magnetosensitivity of biological flavin semiquinone/superoxide radical pairs.
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spelling doaj-art-87774dc728c141db8768d3ca0847c22d2025-08-20T01:58:08ZengElsevierComputational and Structural Biotechnology Journal2001-03702024-12-0126112110.1016/j.csbj.2023.12.009Avian cryptochrome 4 binds superoxideJean Deviers0Fabien Cailliez1Aurélien de la Lande2Daniel R. Kattnig3Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon, EX4 4QD, United Kingdom; Institut de Chimie Physique, CNRS UMR 8000, Université Paris-Saclay, 91405 Orsay, FranceInstitut de Chimie Physique, CNRS UMR 8000, Université Paris-Saclay, 91405 Orsay, FranceInstitut de Chimie Physique, CNRS UMR 8000, Université Paris-Saclay, 91405 Orsay, FranceLiving Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon, EX4 4QD, United Kingdom; Corresponding author.Flavin-binding cryptochromes are blue-light sensitive photoreceptors that have been implicated with magnetoreception in some species. The photocycle involves an intra-protein photo-reduction of the flavin cofactor, generating a magnetosensitive radical pair, and its subsequent re-oxidation. Superoxide (O2•−) is generated in the re-oxidation with molecular oxygen. The resulting O2•−-containing radical pairs have also been hypothesised to underpin various magnetosensitive traits, but due to fast spin relaxation when tumbling in solution would require immobilisation. We here describe our insights in the binding of superoxide to cryptochrome 4 from C. livia based on extensive all-atom molecular dynamics studies and density-functional theory calculations. The positively charged “crypt” region that leads to the flavin binding pocket transiently binds O2•− at 5 flexible binding sites centred on arginine residues. Typical binding times amounted to tens of nanoseconds, but exceptional binding events extended to several hundreds of nanoseconds and slowed the rotational diffusion, thereby realising rotational correlation times as large as 1 ns. The binding sites are particularly efficient in scavenging superoxide escaping from a putative generation site close to the flavin-cofactor, possibly implying a functional relevance. We discuss our findings in view of a potential magnetosensitivity of biological flavin semiquinone/superoxide radical pairs.http://www.sciencedirect.com/science/article/pii/S200103702300483X
spellingShingle Jean Deviers
Fabien Cailliez
Aurélien de la Lande
Daniel R. Kattnig
Avian cryptochrome 4 binds superoxide
Computational and Structural Biotechnology Journal
title Avian cryptochrome 4 binds superoxide
title_full Avian cryptochrome 4 binds superoxide
title_fullStr Avian cryptochrome 4 binds superoxide
title_full_unstemmed Avian cryptochrome 4 binds superoxide
title_short Avian cryptochrome 4 binds superoxide
title_sort avian cryptochrome 4 binds superoxide
url http://www.sciencedirect.com/science/article/pii/S200103702300483X
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AT fabiencailliez aviancryptochrome4bindssuperoxide
AT aureliendelalande aviancryptochrome4bindssuperoxide
AT danielrkattnig aviancryptochrome4bindssuperoxide