1
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Deviers J, Cailliez F, de la Lande A, Kattnig DR. Avian cryptochrome 4 binds superoxide. Comput Struct Biotechnol J 2024; 26:11-21. [PMID: 38204818 PMCID: PMC10776438 DOI: 10.1016/j.csbj.2023.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/06/2023] [Accepted: 12/12/2023] [Indexed: 01/12/2024] Open
Abstract
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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Affiliation(s)
- Jean Deviers
- Living 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, France
| | - Fabien Cailliez
- Institut de Chimie Physique, CNRS UMR 8000, Université Paris-Saclay, 91405 Orsay, France
| | - Aurélien de la Lande
- Institut de Chimie Physique, CNRS UMR 8000, Université Paris-Saclay, 91405 Orsay, France
| | - Daniel R. Kattnig
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon, EX4 4QD, United Kingdom
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2
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DeOliveira CC, Crane BR. A structural decryption of cryptochromes. Front Chem 2024; 12:1436322. [PMID: 39220829 PMCID: PMC11362059 DOI: 10.3389/fchem.2024.1436322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Accepted: 08/01/2024] [Indexed: 09/04/2024] Open
Abstract
Cryptochromes (CRYs), which are signaling proteins related to DNA photolyases, play pivotal roles in sensory responses throughout biology, including growth and development, metabolic regulation, circadian rhythm entrainment and geomagnetic field sensing. This review explores the evolutionary relationships and functional diversity of cryptochromes from the perspective of their molecular structures. In general, CRY biological activities derive from their core structural architecture, which is based on a Photolyase Homology Region (PHR) and a more variable and functionally specific Cryptochrome C-terminal Extension (CCE). The α/β and α-helical domains within the PHR bind FAD, modulate redox reactive residues, accommodate antenna cofactors, recognize small molecules and provide conformationally responsive interaction surfaces for a range of partners. CCEs add structural complexity and divergence, and in doing so, influence photoreceptor reactivity and tailor function. Primary and secondary pockets within the PHR bind myriad moieties and collaborate with the CCEs to tune recognition properties and propagate chemical changes to downstream partners. For some CRYs, changes in homo and hetero-oligomerization couple to light-induced conformational changes, for others, changes in posttranslational modifications couple to cascades of protein interactions with partners and effectors. The structural exploration of cryptochromes underscores how a broad family of signaling proteins with close relationship to light-dependent enzymes achieves a wide range of activities through conservation of key structural and chemical properties upon which function-specific features are elaborated.
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Affiliation(s)
| | - Brian R. Crane
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, United States
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3
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Kretschmer K, Frederiksen A, Reinholdt P, Kongsted J, Solov’yov IA. Understanding the Red Shift in the Absorption Spectrum of the FAD Cofactor in ClCry4 Protein. J Phys Chem B 2024; 128:5320-5326. [PMID: 38805723 PMCID: PMC11163422 DOI: 10.1021/acs.jpcb.4c00710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 05/03/2024] [Accepted: 05/16/2024] [Indexed: 05/30/2024]
Abstract
It is still a puzzle that has not been entirely solved how migratory birds utilize the Earth's magnetic field for biannual migration. The most consistent explanation thus far is rooted in the modulation of the biological function of the cryptochrome 4 (Cry4) protein by an external magnetic field. This phenomenon is closely linked with the flavin adenine dinucleotide (FAD) cofactor that is noncovalently bound in the protein. Cry4 is activated by blue light, which is absorbed by the FAD cofactor. Subsequent electron and proton transfers trigger radical pair formation in the protein, which is sensitive to the external magnetic field. An important long-lasting redox state of the FAD cofactor is the signaling (FADH•) state, which is present after the transient electron transfer steps have been completed. Recent experimental efforts succeeded in crystallizing the Cry4 protein from Columbia livia (ClCry4) with all of the important residues needed for protein photoreduction. This specific crystallization of Cry4 protein so far is the only avian cryptochrome crystal structure available, which, however, has great similarity to the Cry4 proteins of night migratory birds. The previous experimental studies of the ClCry4 protein included the absorption properties of the protein in its different redox states. The absorption spectrum of the FADH• state demonstrated a peculiar red shift compared to the photoabsorption properties of the FAD cofactor in its FADH• state in other Cry proteins from other species. The aim of this study is to understand this red shift by employing the tools of computational microscopy and, in particular, a QM/MM approach that relies on the polarizable embedding approximation.
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Affiliation(s)
- Katarina Kretschmer
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky Str. 9-11, 26129 Oldenburg, Germany
| | - Anders Frederiksen
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky Str. 9-11, 26129 Oldenburg, Germany
| | - Peter Reinholdt
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK 5230 Odense, Denmark
| | - Jacob Kongsted
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK 5230 Odense, Denmark
| | - Ilia A. Solov’yov
- Institute of Physics, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky Str. 9-11, 26129 Oldenburg, Germany
- Research Centre for Neurosensory
Science, Carl von Ossietzky Universität
Oldenburg, Carl-von-Ossietzky
Str. 9-11, 26129 Oldenburg, Germany
- Center
for Nanoscale Dynamics (CENAD), Carl von
Ossietzky Universität Oldenburg, Ammerländer Heerstr. 114-118, 26129 Oldenburg, Germany
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4
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Luo J. Sensitivity enhancement of radical-pair magnetoreceptors as a result of spin decoherence. J Chem Phys 2024; 160:074306. [PMID: 38380753 DOI: 10.1063/5.0182172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 01/15/2024] [Indexed: 02/22/2024] Open
Abstract
Electron spin relaxation is, on many occasions, considered an elephant in the room that challenges the idea of a radical-pair compass, a leading hypothesis for the navigation of migratory avian species. It has been widely recognized that an effective radical-pair magnetoreceptor requires a relaxation time that is long enough for an external magnetic field as weak as the geomagnetic field to significantly modify the coherent spin dynamics. However, previous studies proposed that certain spin relaxation, far quicker than the radical recombination reactions, could enhance, rather than degrade, the directional sensitivity of a radical-pair magnetoreceptor. Here, I investigate relaxation effects on the singlet-triplet interconversion of a model radical pair and find that the enhancement effect originates from population relaxation over a period of several microseconds as a result of efficient spin decoherence. Insights into the truncated spin systems shed light on the physics behind them. I further investigate the possibilities of such enhancement in cryptochrome-based magnetoreception, in which electron hopping takes place between tryptophan residues.
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Affiliation(s)
- Jiate Luo
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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5
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Austvold CK, Keable SM, Procopio M, Usselman RJ. Quantitative measurements of reactive oxygen species partitioning in electron transfer flavoenzyme magnetic field sensing. Front Physiol 2024; 15:1348395. [PMID: 38370016 PMCID: PMC10869518 DOI: 10.3389/fphys.2024.1348395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 01/16/2024] [Indexed: 02/20/2024] Open
Abstract
Biological magnetic field sensing that gives rise to physiological responses is of considerable importance in quantum biology. The radical pair mechanism (RPM) is a fundamental quantum process that can explain some of the observed biological magnetic effects. In magnetically sensitive radical pair (RP) reactions, coherent spin dynamics between singlet and triplet pairs are modulated by weak magnetic fields. The resulting singlet and triplet reaction products lead to distinct biological signaling channels and cellular outcomes. A prevalent RP in biology is between flavin semiquinone and superoxide (O2 •-) in the biological activation of molecular oxygen. This RP can result in a partitioning of reactive oxygen species (ROS) products to form either O2 •- or hydrogen peroxide (H2O2). Here, we examine magnetic sensing of recombinant human electron transfer flavoenzyme (ETF) reoxidation by selectively measuring O2 •- and H2O2 product distributions. ROS partitioning was observed between two static magnetic fields at 20 nT and 50 μT, with a 13% decrease in H2O2 singlet products and a 10% increase in O2 •- triplet products relative to 50 µT. RPM product yields were calculated for a realistic flavin/superoxide RP across the range of static magnetic fields, in agreement with experimental results. For a triplet born RP, the RPM also predicts about three times more O2 •- than H2O2, with experimental results exhibiting about four time more O2 •- produced by ETF. The method presented here illustrates the potential of a novel magnetic flavoprotein biological sensor that is directly linked to mitochondria bioenergetics and can be used as a target to study cell physiology.
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Affiliation(s)
- Chase K. Austvold
- Chemistry and Biochemistry, Montana State University, Bozeman, MT, United States
| | - Stephen M. Keable
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Maria Procopio
- Biophysics, Johns Hopkins University, Baltimore, MD, United States
| | - Robert J. Usselman
- Chemistry and Chemical Engineering, Florida Institute of Technology, Melbourne, FL, United States
- Computational Research At Florida Tech, Melbourne, FL, United States
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6
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Galván I, Hassasfar A, Adams B, Petruccione F. Isotope effects on radical pair performance in cryptochrome: A new hypothesis for the evolution of animal migration: The quantum biology of migration. Bioessays 2024; 46:e2300152. [PMID: 37888800 DOI: 10.1002/bies.202300152] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/28/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023]
Abstract
Mechanisms occurring at the atomic level are now known to drive processes essential for life, as revealed by quantum effects on biochemical reactions. Some macroscopic characteristics of organisms may thus show an atomic imprint, which may be transferred across organisms and affect their evolution. This possibility is considered here for the first time, with the aim of elucidating the appearance of an animal innovation with an unclear evolutionary origin: migratory behaviour. This trait may be mediated by a radical pair (RP) mechanism in the retinal flavoprotein cryptochrome, providing essential magnetic orientation for migration. Isotopes may affect the performance of quantum processes through their nuclear spin. Here, we consider a simple model and then apply the standard open quantum system approach to the spin dynamics of cryptochrome RP. We changed the spin quantum number (I) and g-factor of hydrogen and nitrogen isotopes to investigate their effect on RP's yield and magnetic sensitivity. Strong differences arose between isotopes with I = 1 and I = 1/2 in their contribution to cryptochrome magnetic sensitivity, particularly regarding Earth's magnetic field strengths (25-65 µT). In most cases, isotopic substitution improved RP's magnetic sensitivity. Migratory behaviour may thus have been favoured in animals with certain isotopic compositions of cryptochrome.
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Affiliation(s)
- Ismael Galván
- Department of Evolutionary Ecology, National Museum of Natural Sciences, CSIC, Madrid, Spain
| | - Abbas Hassasfar
- Department of Physics, Stellenbosch University, Stellenbosch, South Africa
| | - Betony Adams
- Quantum Research Group, School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
- The Guy Foundation, Beaminster, Dorset, UK
| | - Francesco Petruccione
- Department of Physics, Stellenbosch University, Stellenbosch, South Africa
- School for Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
- National Institute for Theoretical and Computational Sciences (NITheCS), Stellenbosch, South Africa
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7
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Vecheck AM, McNamee CM, Reijo Pera R, Usselman RJ. Magnetic Field Intervention Enhances Cellular Migration Rates in Biological Scaffolds. Bioengineering (Basel) 2023; 11:9. [PMID: 38247887 PMCID: PMC10813414 DOI: 10.3390/bioengineering11010009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/15/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024] Open
Abstract
The impact of magnetic fields on cellular function is diverse but can be described at least in part by the radical pair mechanism (RPM), where magnetic field intervention alters reactive oxygen species (ROS) populations and downstream cellular signaling. Here, cellular migration within three-dimensional scaffolds was monitored in an applied oscillating 1.4 MHz radiofrequency (RF) magnetic field with an amplitude of 10 µT and a static 50 µT magnetic field. Given that cellular bioenergetics can be altered based on applied RF magnetic fields, this study focused on a magnetic field configuration that increased cellular respiration. Results suggest that RF accelerated cell clustering and elongation after 1 day, with increased levels of clustering and cellular linkage after 7 days. Cell distribution analysis within the scaffolds revealed that the clustering rate during the first day was increased nearly five times in the RF environment. Electron microscopy provided additional topological information and verified the development of fibrous networks, with a cell-derived matrix (CDM) visualized after 7 days in samples maintained in RF. This work demonstrates time-dependent cellular migration that may be influenced by quantum biology (QB) processes and downstream oxidative signaling, enhancing cellular migration behavior.
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Affiliation(s)
- Amy M. Vecheck
- Department of Biomedical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA
| | - Cameron M. McNamee
- Department of Mathematics, California Institute of Technology, Pasadena, CA 91125, USA
- McLaughlin Research Institute, Great Falls, MT 59405, USA
| | | | - Robert J. Usselman
- Department of Chemistry and Chemical Engineering, Florida Institute of Technology, Melbourne, FL 32901, USA
- Computational Research At Florida Tech (CRAFT), Florida Institute of Technology, Melbourne, FL 32901, USA
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8
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Zadeh-Haghighi H, Simon C. Magnetic isotope effects: a potential testing ground for quantum biology. Front Physiol 2023; 14:1338479. [PMID: 38148902 PMCID: PMC10750422 DOI: 10.3389/fphys.2023.1338479] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 11/29/2023] [Indexed: 12/28/2023] Open
Abstract
One possible explanation for magnetosensing in biology, such as avian magnetoreception, is based on the spin dynamics of certain chemical reactions that involve radical pairs. Radical pairs have been suggested to also play a role in anesthesia, hyperactivity, neurogenesis, circadian clock rhythm, microtubule assembly, etc. It thus seems critical to probe the credibility of such models. One way to do so is through isotope effects with different nuclear spins. Here we briefly review the papers involving spin-related isotope effects in biology. We suggest studying isotope effects can be an interesting avenue for quantum biology.
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Affiliation(s)
- Hadi Zadeh-Haghighi
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Christoph Simon
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
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9
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Salerno KM, Domenico J, Le NQ, Balakrishnan K, McQuillen RJ, Stiles CD, Solov'yov IA, Martino CF. Long-Time Oxygen and Superoxide Localization in Arabidopsis thaliana Cryptochrome. J Chem Inf Model 2023; 63:6756-6767. [PMID: 37874902 DOI: 10.1021/acs.jcim.3c00325] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Cryptochromes are proteins that are highly conserved across species and in many instances bind the flavin adenine dinucleotide (FAD) cofactor within their photolyase-homology region (PHR) domain. The FAD cofactor has multiple redox states that help catalyze reactions, and absorbs photons at about 450 nm, a feature linked to the light-related functions of cryptochrome proteins. Reactive oxygen species (ROS) are produced from redox reactions involving molecular oxygen and are involved in a myriad of biological processes. Superoxide O2•- is an exemplary ROS that may be formed through electron transfer from FAD to O2, generating an electron radical pair. Although the formation of a superoxide-FAD radical pair has been speculated, it is still unclear if the required process steps could be realized in cryptochrome. Here, we present results from molecular dynamics (MD) simulations of oxygen interacting with the PHR domain of Arabidopsis thaliana cryptochrome 1 (AtCRY1). Using MD simulation trajectories, oxygen binding locations are characterized through both the O2-FAD intermolecular distance and the local protein environment. Oxygen unbinding times are characterized through replica simulations of the bound oxygen. Simulations reveal that oxygen molecules can localize at certain sites within the cryptochrome protein for tens of nanoseconds, and superoxide molecules can localize for significantly longer. This relatively long-duration molecule binding suggests the possibility of an electron-transfer reaction leading to superoxide formation. Estimates of electron-transfer rates using the Marcus theory are performed for the identified potential binding sites. Molecular oxygen binding results are compared with recent results demonstrating long-time oxygen binding within the electron-transfer flavoprotein (ETF), another FAD binding protein.
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Affiliation(s)
- K Michael Salerno
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Janna Domenico
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Nam Q Le
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Krithika Balakrishnan
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Ryan J McQuillen
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Christopher D Stiles
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
| | - Ilia A Solov'yov
- Institute of Physics, Carl von Ossietzky University Oldenburg, Carl von Ossietzky Straße 9-11, 26129 Oldenburg, Germany
- Centre for Nanoscale Dynamics (CENAD), Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky Straße 9-11, 26129 Oldenburg, Germany
- Centre for Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky Straße 9-11, 26129 Oldenburg, Germany
| | - Carlos F Martino
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, United States
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10
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Luo J. On the anisotropic weak magnetic field effect in radical-pair reactions. J Chem Phys 2023; 158:234302. [PMID: 37318169 DOI: 10.1063/5.0149644] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/30/2023] [Indexed: 06/16/2023] Open
Abstract
For more than 60 years, scientists have been fascinated by the fact that magnetic fields even weaker than internal hyperfine fields can markedly affect spin-selective radical-pair reactions. This weak magnetic field effect has been found to arise from the removal of degeneracies in the zero-field spin Hamiltonian. Here, I investigated the anisotropic effect of a weak magnetic field on a model radical pair with an axially symmetric hyperfine interaction. I found that S-T± and T0-T± interconversions driven by the smaller x and y-components of the hyperfine interaction can be hindered or enhanced by a weak external magnetic field, depending on its direction. Additional isotropically hyperfine-coupled nuclear spins preserve this conclusion, although the S → T± and T0 → T± transitions become asymmetric. These results are supported by simulating reaction yields of a more biologically plausible, flavin-based radical pair.
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Affiliation(s)
- Jiate Luo
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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11
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Matysik J, Gerhards L, Theiss T, Timmermann L, Kurle-Tucholski P, Musabirova G, Qin R, Ortmann F, Solov'yov IA, Gulder T. Spin Dynamics of Flavoproteins. Int J Mol Sci 2023; 24:ijms24098218. [PMID: 37175925 PMCID: PMC10179055 DOI: 10.3390/ijms24098218] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/19/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
This short review reports the surprising phenomenon of nuclear hyperpolarization occurring in chemical reactions, which is called CIDNP (chemically induced dynamic nuclear polarization) or photo-CIDNP if the chemical reaction is light-driven. The phenomenon occurs in both liquid and solid-state, and electron transfer systems, often carrying flavins as electron acceptors, are involved. Here, we explain the physical and chemical properties of flavins, their occurrence in spin-correlated radical pairs (SCRP) and the possible involvement of flavin-carrying SCRPs in animal magneto-reception at earth's magnetic field.
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Affiliation(s)
- Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany
| | - Luca Gerhards
- Institut für Physik, Carl von Ossietzky Universität Oldenburg, Carl-von Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
| | - Tobias Theiss
- Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
| | - Lisa Timmermann
- Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
| | | | - Guzel Musabirova
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany
| | - Ruonan Qin
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany
| | - Frank Ortmann
- TUM School of Natural Sciences, Technische Universität München, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Ilia A Solov'yov
- Institut für Physik, Carl von Ossietzky Universität Oldenburg, Carl-von Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Research Center for Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Center for Nanoscale Dynamics (CENAD), Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
| | - Tanja Gulder
- Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
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12
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Pažėra G, Benjamin P, Mouritsen H, Hore PJ. Isotope Substitution Effects on the Magnetic Compass Properties of Cryptochrome-Based Radical Pairs: A Computational Study. J Phys Chem B 2023; 127:838-845. [PMID: 36669149 PMCID: PMC9900586 DOI: 10.1021/acs.jpcb.2c05335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 12/29/2022] [Indexed: 01/21/2023]
Abstract
The biophysical mechanism of the magnetic compass sense of migratory songbirds is thought to rely on the photochemical reactions of flavin-containing radical pairs in cryptochrome proteins located in the birds' eyes. A consequence of this hypothesis is that the effect of the Earth's magnetic field on the quantum yields of reaction products should be sensitive to isotopic substitutions that modify the hyperfine interactions in the radicals. In this report, we use spin dynamics simulations to explore the effects of 1H → 2H, 12C → 13C, and 14N → 15N isotopic substitutions on the functioning of cryptochrome 4a as a magnetic direction sensor. Two main conclusions emerge. (1) Uniform deuteration of the flavin chromophore appears to be the best way to boost the anisotropy of the magnetic field effect and to change its symmetry. (2) 13C substitution of three of the 12 flavin carbons, in particular C4, C4a, and C8α, seems to be the best recipe for attenuating the anisotropy. These predictions should give insight into the factors that control the magnetic sensitivity once spectroscopic techniques are available for measuring magnetic field effects on oriented protein samples.
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Affiliation(s)
| | - Philip Benjamin
- Department
of Chemistry, University of Oxford, Oxford OX1 3QZ, U.K.
| | - Henrik Mouritsen
- Institut
für Biologie und Umweltwissenschaften, Carl-von-Ossietzky Universität Oldenburg, Oldenburg 26111, Germany
- Research
Centre for Neurosensory Science, University
of Oldenburg, Oldenburg 26111, Germany
| | - P. J. Hore
- Department
of Chemistry, University of Oxford, Oxford OX1 3QZ, U.K.
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13
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Salerno KM, Domenico J, Le NQ, Stiles CD, Solov’yov IA, Martino CF. Long-Time Oxygen Localization in Electron Transfer Flavoprotein. J Chem Inf Model 2022; 62:4191-4199. [PMID: 35998902 PMCID: PMC9472800 DOI: 10.1021/acs.jcim.2c00430] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Indexed: 11/30/2022]
Abstract
Reactive oxygen species (ROS) exert a wide range of biological effects from beneficial regulatory function to deleterious oxidative stress. The electron transfer flavoprotein (ETF) is ubiquitous to life and is associated with aerobic metabolism and ROS production due to its location in the mitochondria. Quantifying oxygen localization within the ETF complex is critical for understanding the potential for electron transfer and radical pair formation between flavin adenine dinucleotide (FAD) cofactor and superoxide during ROS formation. Our study employed all-atom molecular dynamics simulations and identified several novel, long-lived oxygen binding sites within the ETF complex that appear near the FAD cofactor. Site locations, the local electrostatic environment, and characteristic oxygen binding times for each site were evaluated to establish factors that may lead to possible charge transfer reactions and superoxide formation within the ETF complex. The study revealed that some oxygen binding sites are naturally linked to protein domain features, suggesting opportunities to engineer and control ROS production and subsequent dynamics.
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Affiliation(s)
- K. Michael Salerno
- The
Johns Hopkins University Applied Physics
Laboratory, 11100 Johns
Hopkins Road, Laurel, Maryland 20723, United States
| | - Janna Domenico
- The
Johns Hopkins University Applied Physics
Laboratory, 11100 Johns
Hopkins Road, Laurel, Maryland 20723, United States
| | - Nam Q. Le
- The
Johns Hopkins University Applied Physics
Laboratory, 11100 Johns
Hopkins Road, Laurel, Maryland 20723, United States
| | - Christopher D. Stiles
- The
Johns Hopkins University Applied Physics
Laboratory, 11100 Johns
Hopkins Road, Laurel, Maryland 20723, United States
| | - Ilia A. Solov’yov
- Institute
of Physics, Carl von Ossietzky University
Oldenburg, Carl von Ossietzky
Straße 9-11, 26129 Oldenburg, Germany
- Centre
for Neurosensory Science, Carl von Ossietzky
University Oldenburg, Carl von Ossietzky Straße 9-11, 26129 Oldenburg, Germany
| | - Carlos F. Martino
- The
Johns Hopkins University Applied Physics
Laboratory, 11100 Johns
Hopkins Road, Laurel, Maryland 20723, United States
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14
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Ramsay J, Kattnig DR. Radical triads, not pairs, may explain effects of hypomagnetic fields on neurogenesis. PLoS Comput Biol 2022; 18:e1010519. [PMID: 36108063 PMCID: PMC9514667 DOI: 10.1371/journal.pcbi.1010519] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 09/27/2022] [Accepted: 08/27/2022] [Indexed: 12/03/2022] Open
Abstract
Adult hippocampal neurogenesis and hippocampus-dependent cognition in mice have been found to be adversely affected by hypomagnetic field exposure. The effect concurred with a reduction of reactive oxygen species in the absence of the geomagnetic field. A recent theoretical study suggests a mechanistic interpretation of this phenomenon in the framework of the Radical Pair Mechanism. According to this model, a flavin-superoxide radical pair, born in the singlet spin configuration, undergoes magnetic field-dependent spin dynamics such that the pair's recombination is enhanced as the applied magnetic field is reduced. This model has two ostensible weaknesses: a) the assumption of a singlet initial state is irreconcilable with known reaction pathways generating such radical pairs, and b) the model neglects the swift spin relaxation of free superoxide, which abolishes any magnetic sensitivity in geomagnetic/hypomagnetic fields. We here suggest that a model based on a radical triad and the assumption of a secondary radical scavenging reaction can, in principle, explain the phenomenon without unnatural assumptions, thus providing a coherent explanation of hypomagnetic field effects in biology.
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Affiliation(s)
- Jess Ramsay
- Living Systems Institute and Department of Physics, University of Exeter, Exeter, Devon, United Kingdom
| | - Daniel R. Kattnig
- Living Systems Institute and Department of Physics, University of Exeter, Exeter, Devon, United Kingdom
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15
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Zadeh-Haghighi H, Simon C. Magnetic field effects in biology from the perspective of the radical pair mechanism. J R Soc Interface 2022; 19:20220325. [PMID: 35919980 PMCID: PMC9346374 DOI: 10.1098/rsif.2022.0325] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 07/14/2022] [Indexed: 04/07/2023] Open
Abstract
Hundreds of studies have found that weak magnetic fields can significantly influence various biological systems. However, the underlying mechanisms behind these phenomena remain elusive. Remarkably, the magnetic energies implicated in these effects are much smaller than thermal energies. Here, we review these observations, and we suggest an explanation based on the radical pair mechanism, which involves the quantum dynamics of the electron and nuclear spins of transient radical molecules. While the radical pair mechanism has been studied in detail in the context of avian magnetoreception, the studies reviewed here show that magnetosensitivity is widespread throughout biology. We review magnetic field effects on various physiological functions, discussing static, hypomagnetic and oscillating magnetic fields, as well as isotope effects. We then review the radical pair mechanism as a potential unifying model for the described magnetic field effects, and we discuss plausible candidate molecules for the radical pairs. We review recent studies proposing that the radical pair mechanism provides explanations for isotope effects in xenon anaesthesia and lithium treatment of hyperactivity, magnetic field effects on the circadian clock, and hypomagnetic field effects on neurogenesis and microtubule assembly. We conclude by discussing future lines of investigation in this exciting new area of quantum biology.
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Affiliation(s)
- Hadi Zadeh-Haghighi
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Christoph Simon
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta, Canada T2N 1N4
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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16
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Rishabh R, Zadeh-Haghighi H, Salahub D, Simon C. Radical pairs may explain reactive oxygen species-mediated effects of hypomagnetic field on neurogenesis. PLoS Comput Biol 2022; 18:e1010198. [PMID: 35653379 PMCID: PMC9197044 DOI: 10.1371/journal.pcbi.1010198] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 06/14/2022] [Accepted: 05/11/2022] [Indexed: 12/21/2022] Open
Abstract
Exposures to a hypomagnetic field can affect biological processes. Recently, it has been observed that hypomagnetic field exposure can adversely affect adult hippocampal neurogenesis and hippocampus-dependent cognition in mice. In the same study, the role of reactive oxygen species (ROS) in hypomagnetic field effects has been demonstrated. However, the mechanistic reasons behind this effect are not clear. This study proposes a radical pair mechanism based on a flavin-superoxide radical pair to explain the modulation of ROS production and the attenuation of adult hippocampal neurogenesis in a hypomagnetic field. The results of our calculations favor a singlet-born radical pair over a triplet-born radical pair. Our model predicts hypomagnetic field effects on the triplet/singlet yield of comparable strength as the effects observed in experimental studies on adult hippocampal neurogenesis. Our predictions are in qualitative agreement with experimental results on superoxide concentration and other observed ROS effects. We also predict the effects of applied magnetic fields and oxygen isotopic substitution on adult hippocampal neurogenesis.
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Affiliation(s)
- Rishabh Rishabh
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
- Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Hadi Zadeh-Haghighi
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
- Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Dennis Salahub
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
- Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta, Canada
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada
- Centre for Molecular Simulation, University of Calgary, Calgary, Alberta, Canada
| | - Christoph Simon
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
- Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
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17
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Human magnetic sense is mediated by a light and magnetic field resonance-dependent mechanism. Sci Rep 2022; 12:8997. [PMID: 35637212 PMCID: PMC9151822 DOI: 10.1038/s41598-022-12460-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 05/10/2022] [Indexed: 11/13/2022] Open
Abstract
Numerous organisms use the Earth’s magnetic field as a sensory cue for migration, body alignment, or food search. Despite some contradictory reports, yet it is generally accepted that humans do not sense the geomagnetic field. Here, we demonstrate that a magnetic field resonance mechanism mediates light-dependent magnetic orientation in men, using a rotary chair experiment combined with a two-alternative forced choice paradigm. Two groups of subjects were classified with different magnetic orientation tendencies depending on the food context. Magnetic orientation of the subjects was sensitive to the wavelength of incident light and was critically dependent on blue light reaching the eyes. Importantly, it appears that a magnetic field resonance-dependent mechanism mediates these responses, as evidenced by disruption or augmentation of the ability to orient by radiofrequency magnetic fields at the Larmor frequency and the dependence of these effects on the angle between the radiofrequency and geomagnetic fields. Furthermore, inversion of the vertical component of the geomagnetic field revealed a non-canonical inclination compass effect on the magnetic orientation. These results establish the existence of a human magnetic sense and suggest an underlying quantum mechanical magnetoreception mechanism.
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18
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Zadeh-Haghighi H, Simon C. Radical pairs may play a role in microtubule reorganization. Sci Rep 2022; 12:6109. [PMID: 35414166 PMCID: PMC9005667 DOI: 10.1038/s41598-022-10068-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 04/01/2022] [Indexed: 12/14/2022] Open
Abstract
The exact mechanism behind general anesthesia remains an open question in neuroscience. It has been proposed that anesthetics selectively prevent consciousness and memory via acting on microtubules (MTs). It is known that the magnetic field modulates MT organization. A recent study shows that a radical pair model can explain the isotope effect in xenon-induced anesthesia and predicts magnetic field effects on anesthetic potency. Further, reactive oxygen species are also implicated in MT stability and anesthesia. Based on a simple radical pair mechanism model and a simple mathematical model of MT organization, we show that magnetic fields can modulate spin dynamics of naturally occurring radical pairs in MT. We propose that the spin dynamics influence a rate in the reaction cycle, which translates into a change in the MT density. We can reproduce magnetic field effects on the MT concentration that have been observed. Our model also predicts additional effects at slightly higher fields. Our model further predicts that the effect of zinc on the MT density exhibits isotopic dependence. The findings of this work make a connection between microtubule-based and radical pair-based quantum theories of consciousness.
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Affiliation(s)
- Hadi Zadeh-Haghighi
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
| | - Christoph Simon
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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19
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Smith LD, Deviers J, Kattnig DR. Observations about utilitarian coherence in the avian compass. Sci Rep 2022; 12:6011. [PMID: 35397661 PMCID: PMC8994785 DOI: 10.1038/s41598-022-09901-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/29/2022] [Indexed: 11/09/2022] Open
Abstract
It is hypothesised that the avian compass relies on spin dynamics in a recombining radical pair. Quantum coherence has been suggested as a resource to this process that nature may utilise to achieve increased compass sensitivity. To date, the true functional role of coherence in these natural systems has remained speculative, lacking insights from sufficiently complex models. Here, we investigate realistically large radical pair models with up to 21 nuclear spins, inspired by the putative magnetosensory protein cryptochrome. By varying relative radical orientations, we reveal correlations of several coherence measures with compass fidelity. Whilst electronic coherence is found to be an ineffective predictor of compass sensitivity, a robust correlation of compass sensitivity and a global coherence measure is established. The results demonstrate the importance of realistic models, and appropriate choice of coherence measure, in elucidating the quantum nature of the avian compass.
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Affiliation(s)
- Luke D Smith
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Jean Deviers
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Daniel R Kattnig
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
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20
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Deviers J, Cailliez F, de la Lande A, Kattnig DR. Anisotropic magnetic field effects in the re-oxidation of cryptochrome in the presence of scavenger radicals. J Chem Phys 2022; 156:025101. [PMID: 35032990 DOI: 10.1063/5.0078115] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The avian compass and many other of nature's magnetoreceptive traits are widely ascribed to the protein cryptochrome. There, magnetosensitivity is thought to emerge as the spin dynamics of radicals in the applied magnetic field enters in competition with their recombination. The first and dominant model makes use of a radical pair. However, recent studies have suggested that magnetosensitivity could be markedly enhanced for a radical triad, the primary radical pair of which undergoes a spin-selective recombination reaction with a third radical. Here, we test the practicality of this supposition for the reoxidation reaction of the reduced FAD cofactor in cryptochrome, which has been implicated with light-independent magnetoreception but appears irreconcilable with the classical radical pair mechanism (RPM). Based on the available realistic cryptochrome structures, we predict the magnetosensitivity of radical triad systems comprising the flavin semiquinone, the superoxide, and a tyrosine or ascorbyl scavenger radical. We consider many hyperfine-coupled nuclear spins, the relative orientation and placement of the radicals, their coupling by the electron-electron dipolar interaction, and spin relaxation in the superoxide radical in the limit of instantaneous decoherence, which have not been comprehensively considered before. We demonstrate that these systems can provide superior magnetosensitivity under realistic conditions, with implications for dark-state cryptochrome magnetoreception and other biological magneto- and isotope-sensitive radical recombination reactions.
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Affiliation(s)
- Jean Deviers
- Department of Physics and Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD Exeter, United Kingdom
| | - Fabien Cailliez
- Institut de Chimie Physique, Université Paris Saclay, CNRS (UMR 8000), 15 avenue Jean Perrin, 91405 Orsay, France
| | - Aurélien de la Lande
- Institut de Chimie Physique, Université Paris Saclay, CNRS (UMR 8000), 15 avenue Jean Perrin, 91405 Orsay, France
| | - Daniel R Kattnig
- Department of Physics and Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD Exeter, United Kingdom
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21
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Broadband 75-85 MHz radiofrequency fields disrupt magnetic compass orientation in night-migratory songbirds consistent with a flavin-based radical pair magnetoreceptor. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:97-106. [PMID: 35019998 PMCID: PMC8918455 DOI: 10.1007/s00359-021-01537-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 12/15/2021] [Accepted: 12/17/2021] [Indexed: 12/20/2022]
Abstract
The light-dependent magnetic compass sense of night-migratory songbirds can be disrupted by weak radiofrequency fields. This finding supports a quantum mechanical, radical-pair-based mechanism of magnetoreception as observed for isolated cryptochrome 4, a protein found in birds’ retinas. The exact identity of the magnetically sensitive radicals in cryptochrome is uncertain in vivo, but their formation seems to require a bound flavin adenine dinucleotide chromophore and a chain of four tryptophan residues within the protein. Resulting from the hyperfine interactions of nuclear spins with the unpaired electrons, the sensitivity of the radicals to radiofrequency magnetic fields depends strongly on the number of magnetic nuclei (hydrogen and nitrogen atoms) they contain. Quantum-chemical calculations suggested that electromagnetic noise in the frequency range 75–85 MHz could give information about the identity of the radicals involved. Here, we show that broadband 75–85 MHz radiofrequency fields prevent a night-migratory songbird from using its magnetic compass in behavioural experiments. These results indicate that at least one of the components of the radical pair involved in the sensory process of avian magnetoreception must contain a substantial number of strong hyperfine interactions as would be the case if a flavin–tryptophan radical pair were the magnetic sensor.
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22
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Zadeh-Haghighi H, Simon C. Radical pairs can explain magnetic field and lithium effects on the circadian clock. Sci Rep 2022; 12:269. [PMID: 34997158 PMCID: PMC8742017 DOI: 10.1038/s41598-021-04334-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 12/14/2021] [Indexed: 12/21/2022] Open
Abstract
Drosophila's circadian clock can be perturbed by magnetic fields, as well as by lithium administration. Cryptochromes are critical for the circadian clock. Further, the radical pairs in cryptochrome also can explain magnetoreception in animals. Based on a simple radical pair mechanism model of the animal magnetic compass, we show that both magnetic fields and lithium can influence the spin dynamics of the naturally occurring radical pairs and hence modulate the circadian clock's rhythms. Using a simple chemical oscillator model for the circadian clock, we show that the spin dynamics influence a rate in the chemical oscillator model, which translates into a change in the circadian period. Our model can reproduce the results of two independent experiments, magnetic field and lithium effects on the circadian clock. Our model predicts that stronger magnetic fields would shorten the clock's period. We also predict that lithium influences the clock in an isotope-dependent manner. Furthermore, our model also predicts that magnetic fields and hyperfine interactions modulate oxidative stress. The findings of this work suggest that the quantum nature of radical pairs might play roles in the brain, as another piece of evidence in addition to recent results on xenon anesthesia and lithium effects on hyperactivity.
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Affiliation(s)
- Hadi Zadeh-Haghighi
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
| | - Christoph Simon
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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23
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Babcock N, Kattnig DR. Radical Scavenging Could Answer the Challenge Posed by Electron-Electron Dipolar Interactions in the Cryptochrome Compass Model. JACS AU 2021; 1:2033-2046. [PMID: 34841416 PMCID: PMC8611662 DOI: 10.1021/jacsau.1c00332] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Indexed: 06/13/2023]
Abstract
Many birds are endowed with a visual magnetic sense that may exploit magnetosensitive radical recombination processes in the protein cryptochrome. In this widely accepted but unproven model, geomagnetic sensitivity is suggested to arise from variations in the recombination rate of a pair of radicals, whose unpaired electron spins undergo coherent singlet-triplet interconversion in the geomagnetic field by coupling to nuclear spins via hyperfine interactions. However, simulations of this conventional radical pair mechanism (RPM) predicted only tiny magnetosensitivities for realistic conditions because the RPM's directional sensitivity is strongly suppressed by the intrinsic electron-electron dipolar (EED) interactions, casting doubt on its viability as a magnetic sensor. We show how this RPM-suppression problem is overcome in a three-radical system in which a third "scavenger" radical reacts with one member of the primary pair. We use this finding to predict substantial magnetic field effects that exceed those of the RPM in the presence of EED interactions in animal cryptochromes.
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Affiliation(s)
- Nathan
Sean Babcock
- Quantum
Biology Laboratory, Howard University, 2400 Sixth Street NW, Washington District of Columbia, 20059, United States of America
- Living
Systems Institute and Department of Physics University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom
| | - Daniel R. Kattnig
- Living
Systems Institute and Department of Physics University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom
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24
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Wong SY, Wei Y, Mouritsen H, Solov'yov IA, Hore PJ. Cryptochrome magnetoreception: four tryptophans could be better than three. J R Soc Interface 2021; 18:20210601. [PMID: 34753309 PMCID: PMC8580466 DOI: 10.1098/rsif.2021.0601] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 10/14/2021] [Indexed: 12/28/2022] Open
Abstract
The biophysical mechanism of the magnetic compass sensor in migratory songbirds is thought to involve photo-induced radical pairs formed in cryptochrome (Cry) flavoproteins located in photoreceptor cells in the eyes. In Cry4a-the most likely of the six known avian Crys to have a magnetic sensing function-four radical pair states are formed sequentially by the stepwise transfer of an electron along a chain of four tryptophan residues to the photo-excited flavin. In purified Cry4a from the migratory European robin, the third of these flavin-tryptophan radical pairs is more magnetically sensitive than the fourth, consistent with the smaller separation of the radicals in the former. Here, we explore the idea that these two radical pair states of Cry4a could exist in rapid dynamic equilibrium such that the key magnetic and kinetic properties are weighted averages. Spin dynamics simulations suggest that the third radical pair is largely responsible for magnetic sensing while the fourth may be better placed to initiate magnetic signalling particularly if the terminal tryptophan radical can be reduced by a nearby tyrosine. Such an arrangement could have allowed independent optimization of the essential sensing and signalling functions of the protein. It might also rationalize why avian Cry4a has four tryptophans while Crys from plants have only three.
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Affiliation(s)
- Siu Ying Wong
- Institut für Physik, Carl-von-Ossietzky Universität Oldenburg, Oldenburg 26111, Germany
| | - Yujing Wei
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK
| | - Henrik Mouritsen
- Institut für Biologie und Umweltwissenschaften, Carl-von-Ossietzky Universität Oldenburg, Oldenburg 26111, Germany
- Research Centre for Neurosensory Science, University of Oldenburg, Oldenburg 26111, Germany
| | - Ilia A. Solov'yov
- Institut für Physik, Carl-von-Ossietzky Universität Oldenburg, Oldenburg 26111, Germany
| | - P. J. Hore
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK
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25
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Park J, Koehler F, Varnavides G, Antonini M, Anikeeva P. Influence of Magnetic Fields on Electrochemical Reactions of Redox Cofactor Solutions. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jimin Park
- Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA
- Research Laboratory of Electronics and McGovern Institute for Brain Research Massachusetts Institute of Technology Cambridge MA 02139 USA
| | - Florian Koehler
- Research Laboratory of Electronics and McGovern Institute for Brain Research Massachusetts Institute of Technology Cambridge MA 02139 USA
- Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA 02139 USA
| | - Georgios Varnavides
- Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA
- Research Laboratory of Electronics and McGovern Institute for Brain Research Massachusetts Institute of Technology Cambridge MA 02139 USA
| | - Marc‐Joseph Antonini
- Research Laboratory of Electronics and McGovern Institute for Brain Research Massachusetts Institute of Technology Cambridge MA 02139 USA
- Harvard/MIT Health Science & Technology Graduate Program Cambridge MA 02139 USA
| | - Polina Anikeeva
- Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA
- Research Laboratory of Electronics and McGovern Institute for Brain Research Massachusetts Institute of Technology Cambridge MA 02139 USA
- Department of Brain and Cognitive Sciences Massachusetts Institute of Technology Cambridge MA 02139 USA
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26
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Park J, Koehler F, Varnavides G, Antonini MJ, Anikeeva P. Influence of Magnetic Fields on Electrochemical Reactions of Redox Cofactor Solutions. Angew Chem Int Ed Engl 2021; 60:18295-18302. [PMID: 34097813 DOI: 10.1002/anie.202106288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Indexed: 11/06/2022]
Abstract
Redox cofactors mediate many enzymatic processes and are increasingly employed in biomedical and energy applications. Exploring the influence of external magnetic fields on redox cofactor chemistry can enhance our understanding of magnetic-field-sensitive biological processes and allow the application of magnetic fields to modulate redox reactions involving cofactors. Through a combination of experiments and modeling, we investigate the influence of magnetic fields on electrochemical reactions in redox cofactor solutions. By employing flavin mononucleotide (FMN) cofactor as a model system, we characterize magnetically induced changes in Faradaic currents. We find that radical pair intermediates have negligible influence on current increases in FMN solution upon application of a magnetic field. The dominant mechanism underlying the observed current increases is the magneto-hydrodynamic effect. We extend our analyses to other diffusion-limited electrochemical reactions of redox cofactor solutions and arrive at similar conclusions, highlighting the opportunity to use this framework in redox cofactor chemistry.
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Affiliation(s)
- Jimin Park
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Research Laboratory of Electronics and McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Florian Koehler
- Research Laboratory of Electronics and McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Georgios Varnavides
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Research Laboratory of Electronics and McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Marc-Joseph Antonini
- Research Laboratory of Electronics and McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Harvard/MIT Health Science & Technology Graduate Program, Cambridge, MA, 02139, USA
| | - Polina Anikeeva
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Research Laboratory of Electronics and McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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27
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Castello P, Jimenez P, Martino CF. The Role of Pulsed Electromagnetic Fields on the Radical Pair Mechanism. Bioelectromagnetics 2021; 42:491-500. [PMID: 34224591 DOI: 10.1002/bem.22358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 06/08/2021] [Accepted: 06/19/2021] [Indexed: 11/09/2022]
Abstract
In recent decades, the use of pulsed electromagnetic fields (PEMF) in therapeutics has been one of the main fields of activity in the bioelectromagnetics arena. Nevertheless, progress in this area has been hindered by the lack of consensus on a biophysical mechanism of interaction that can satisfactorily explain how low-level, non-thermal electromagnetic fields would be able to sufficiently affect chemistry as to elicit biological effects in living organisms. This specifically applies in cases where the induced electric fields are too small to generate a biological response of any consequence. A growing body of experimental observations that would explain the nature of these effects speaks strongly about the involvement of a theory known as the radical pair mechanism (RPM). This mechanism explains how a pair of reactive oxygen species with distinct chemical fate can be influenced by a low-level external magnetic field through Zeeman and hyperfine interactions. So far, a study of the effects of complex spatiotemporal signals within the context of the RPM has not been performed. Here, we present a computational investigation of such effects by utilizing a generic PEMF test signal and RPM models of different complexity. Surprisingly, our results show how substantially different chemical results can be obtained within ranges that depend on the specific orientation of the PEMF test signal with respect to the background static magnetic field, its waveform, and both of their amplitudes. These results provide a basis for explaining the distinctive biological relevance of PEMF signals on radical pair chemical reactions. © 2021 Bioelectromagnetics Society.
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Affiliation(s)
- Pablo Castello
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Belgrano, Buenos Aires, Argentina
| | - Pablo Jimenez
- Centro Atómico Bariloche, CONICET, CNEA, S. C. de Bariloche, Argentina
| | - Carlos F Martino
- Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland
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28
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Zadeh-Haghighi H, Simon C. Entangled radicals may explain lithium effects on hyperactivity. Sci Rep 2021; 11:12121. [PMID: 34108537 PMCID: PMC8190433 DOI: 10.1038/s41598-021-91388-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/26/2021] [Indexed: 02/05/2023] Open
Abstract
It is known that bipolar disorder and its lithium treatment involve the modulation of oxidative stress. Moreover, it has been observed that lithium's effects are isotope-dependent. Based on these findings, here we propose that lithium exerts its effects by influencing the recombination dynamics of a naturally occurring radical pair involving oxygen. We develop a simple model inspired by the radical-pair mechanism in cryptochrome in the context of avian magnetoreception and xenon-induced anesthesia. Our model reproduces the observed isotopic dependence in the lithium treatment of hyperactivity in rats. It predicts a magnetic-field dependence of the effectiveness of lithium, which provides one potential experimental test of our hypothesis. Our findings show that Nature might harness quantum entanglement for the brain's cognitive processes.
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Affiliation(s)
- Hadi Zadeh-Haghighi
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Quantum Alberta, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
| | - Christoph Simon
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Quantum Alberta, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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Magnetic sensitivity of cryptochrome 4 from a migratory songbird. Nature 2021; 594:535-540. [PMID: 34163056 DOI: 10.1038/s41586-021-03618-9] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 05/06/2021] [Indexed: 02/06/2023]
Abstract
Night-migratory songbirds are remarkably proficient navigators1. Flying alone and often over great distances, they use various directional cues including, crucially, a light-dependent magnetic compass2,3. The mechanism of this compass has been suggested to rely on the quantum spin dynamics of photoinduced radical pairs in cryptochrome flavoproteins located in the retinas of the birds4-7. Here we show that the photochemistry of cryptochrome 4 (CRY4) from the night-migratory European robin (Erithacus rubecula) is magnetically sensitive in vitro, and more so than CRY4 from two non-migratory bird species, chicken (Gallus gallus) and pigeon (Columba livia). Site-specific mutations of ErCRY4 reveal the roles of four successive flavin-tryptophan radical pairs in generating magnetic field effects and in stabilizing potential signalling states in a way that could enable sensing and signalling functions to be independently optimized in night-migratory birds.
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Wiltschko R, Nießner C, Wiltschko W. The Magnetic Compass of Birds: The Role of Cryptochrome. Front Physiol 2021; 12:667000. [PMID: 34093230 PMCID: PMC8171495 DOI: 10.3389/fphys.2021.667000] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/08/2021] [Indexed: 12/28/2022] Open
Abstract
The geomagnetic field provides directional information for birds. The avian magnetic compass is an inclination compass that uses not the polarity of the magnetic field but the axial course of the field lines and their inclination in space. It works in a flexible functional window, and it requires short-wavelength light. These characteristics result from the underlying sensory mechanism based on radical pair processes in the eyes, with cryptochrome suggested as the receptor molecule. The chromophore of cryptochrome, flavin adenine dinucleotide (FAD), undergoes a photocycle, where radical pairs are formed during photo-reduction as well as during re-oxidation; behavioral data indicate that the latter is crucial for detecting magnetic directions. Five types of cryptochromes are found in the retina of birds: cryptochrome 1a (Cry1a), cryptochrome 1b, cryptochrome 2, cryptochrome 4a, and cryptochrome 4b. Because of its location in the outer segments of the ultraviolet cones with their clear oil droplets, Cry1a appears to be the most likely receptor molecule for magnetic compass information.
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Affiliation(s)
- Roswitha Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Christine Nießner
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Wolfgang Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
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Smith J, Zadeh Haghighi H, Salahub D, Simon C. Radical pairs may play a role in xenon-induced general anesthesia. Sci Rep 2021; 11:6287. [PMID: 33737599 PMCID: PMC7973516 DOI: 10.1038/s41598-021-85673-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 03/03/2021] [Indexed: 02/06/2023] Open
Abstract
Understanding the mechanisms underlying general anesthesia would be a key step towards understanding consciousness. The process of xenon-induced general anesthesia has been shown to involve electron transfer, and the potency of xenon as a general anesthetic exhibits isotopic dependence. We propose that these observations can be explained by a mechanism in which the xenon nuclear spin influences the recombination dynamics of a naturally occurring radical pair of electrons. We develop a simple model inspired by the body of work on the radical-pair mechanism in cryptochrome in the context of avian magnetoreception, and we show that our model can reproduce the observed isotopic dependence of the general anesthetic potency of xenon in mice. Our results are consistent with the idea that radical pairs of electrons with entangled spins could be important for consciousness.
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Affiliation(s)
- Jordan Smith
- Department of Physics and Astronomy, Institute for Quantum Science and Technology, Quantum Alberta, and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
| | - Hadi Zadeh Haghighi
- Department of Physics and Astronomy, Institute for Quantum Science and Technology, Quantum Alberta, and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Dennis Salahub
- Department of Chemistry, Department of Physics and Astronomy, Institute for Quantum Science and Technology, Quantum Alberta, Centre for Molecular Simulation, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Christoph Simon
- Department of Physics and Astronomy, Institute for Quantum Science and Technology, Quantum Alberta, and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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Affiliation(s)
- P J Hore
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Konstantin L Ivanov
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Novosibirsk 630090, Russia
| | - Michael R Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
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