Magnetoreception through Cryptochrome may involve superoxide

Ilia Solov'yov, Klaus Schulten

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

In the last decades, it has been demonstrated that many animal species orient in the Earth magnetic field. One of the best-studied examples is the use of the geomagnetic field by migratory birds for orientation and navigation. However, the biophysical mechanism underlying animal magnetoreception is still not understood. One theory for magnetoreception in birds invokes the so-called radical-pair model. This mechanism involves a pair of reactive radicals, whose chemical fate can be influenced by the orientation with respect to the magnetic field of the Earth through Zeeman and hyperfine interactions. The fact that the geomagnetic field is weak, i.e., ~0.5 G, puts a severe constraint on the radical pair that can establish the magnetic compass sense. For a noticeable change of the reaction yield in a redirected geomagnetic field, the hyperfine interaction has to be as weak as the Earth field Zeeman interaction, i.e., unusually weak for an organic compound. Such weak hyperfine interaction can be achieved if one of the radicals is completely devoid of this interaction as realized in a radical pair containing an oxygen molecule as one of the radicals. Accordingly, we investigate here a possible radical pair-based reaction in the photoreceptor cryptochrome that reduces the protein's flavin group from its signaling state FADH$^bullet$ to the inactive state FADH$^–$ (which reacts to the likewise inactive FAD) by means of the superoxide radical, O2$^$. We argue that the spin dynamics in the suggested reaction can act as a geomagnetic compass and that the very low physiological concentration (nM-$M) of otherwise toxic $^$ is sufficient, even favorable, for the biological function.
OriginalsprogEngelsk
TidsskriftBiophysical Journal
Vol/bind96
Sider (fra-til)4804-4813
ISSN0006-3495
StatusUdgivet - 2009

Fingeraftryk

inorganic peroxides
geomagnetism
birds
interactions
animals
magnetic compasses
photoreceptors
spin dynamics
navigation
organic compounds
magnetic fields
proteins
oxygen

Citer dette

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title = "Magnetoreception through Cryptochrome may involve superoxide",
abstract = "In the last decades, it has been demonstrated that many animal species orient in the Earth magnetic field. One of the best-studied examples is the use of the geomagnetic field by migratory birds for orientation and navigation. However, the biophysical mechanism underlying animal magnetoreception is still not understood. One theory for magnetoreception in birds invokes the so-called radical-pair model. This mechanism involves a pair of reactive radicals, whose chemical fate can be influenced by the orientation with respect to the magnetic field of the Earth through Zeeman and hyperfine interactions. The fact that the geomagnetic field is weak, i.e., ~0.5 G, puts a severe constraint on the radical pair that can establish the magnetic compass sense. For a noticeable change of the reaction yield in a redirected geomagnetic field, the hyperfine interaction has to be as weak as the Earth field Zeeman interaction, i.e., unusually weak for an organic compound. Such weak hyperfine interaction can be achieved if one of the radicals is completely devoid of this interaction as realized in a radical pair containing an oxygen molecule as one of the radicals. Accordingly, we investigate here a possible radical pair-based reaction in the photoreceptor cryptochrome that reduces the protein's flavin group from its signaling state FADH$^bullet$ to the inactive state FADH$^–$ (which reacts to the likewise inactive FAD) by means of the superoxide radical, O2$^$. We argue that the spin dynamics in the suggested reaction can act as a geomagnetic compass and that the very low physiological concentration (nM-$M) of otherwise toxic $^$ is sufficient, even favorable, for the biological function.",
author = "Ilia Solov'yov and Klaus Schulten",
year = "2009",
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volume = "96",
pages = "4804--4813",
journal = "Biophysical Journal",
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Magnetoreception through Cryptochrome may involve superoxide. / Solov'yov, Ilia; Schulten, Klaus.

I: Biophysical Journal, Bind 96, 2009, s. 4804-4813.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Magnetoreception through Cryptochrome may involve superoxide

AU - Solov'yov, Ilia

AU - Schulten, Klaus

PY - 2009

Y1 - 2009

N2 - In the last decades, it has been demonstrated that many animal species orient in the Earth magnetic field. One of the best-studied examples is the use of the geomagnetic field by migratory birds for orientation and navigation. However, the biophysical mechanism underlying animal magnetoreception is still not understood. One theory for magnetoreception in birds invokes the so-called radical-pair model. This mechanism involves a pair of reactive radicals, whose chemical fate can be influenced by the orientation with respect to the magnetic field of the Earth through Zeeman and hyperfine interactions. The fact that the geomagnetic field is weak, i.e., ~0.5 G, puts a severe constraint on the radical pair that can establish the magnetic compass sense. For a noticeable change of the reaction yield in a redirected geomagnetic field, the hyperfine interaction has to be as weak as the Earth field Zeeman interaction, i.e., unusually weak for an organic compound. Such weak hyperfine interaction can be achieved if one of the radicals is completely devoid of this interaction as realized in a radical pair containing an oxygen molecule as one of the radicals. Accordingly, we investigate here a possible radical pair-based reaction in the photoreceptor cryptochrome that reduces the protein's flavin group from its signaling state FADH$^bullet$ to the inactive state FADH$^–$ (which reacts to the likewise inactive FAD) by means of the superoxide radical, O2$^$. We argue that the spin dynamics in the suggested reaction can act as a geomagnetic compass and that the very low physiological concentration (nM-$M) of otherwise toxic $^$ is sufficient, even favorable, for the biological function.

AB - In the last decades, it has been demonstrated that many animal species orient in the Earth magnetic field. One of the best-studied examples is the use of the geomagnetic field by migratory birds for orientation and navigation. However, the biophysical mechanism underlying animal magnetoreception is still not understood. One theory for magnetoreception in birds invokes the so-called radical-pair model. This mechanism involves a pair of reactive radicals, whose chemical fate can be influenced by the orientation with respect to the magnetic field of the Earth through Zeeman and hyperfine interactions. The fact that the geomagnetic field is weak, i.e., ~0.5 G, puts a severe constraint on the radical pair that can establish the magnetic compass sense. For a noticeable change of the reaction yield in a redirected geomagnetic field, the hyperfine interaction has to be as weak as the Earth field Zeeman interaction, i.e., unusually weak for an organic compound. Such weak hyperfine interaction can be achieved if one of the radicals is completely devoid of this interaction as realized in a radical pair containing an oxygen molecule as one of the radicals. Accordingly, we investigate here a possible radical pair-based reaction in the photoreceptor cryptochrome that reduces the protein's flavin group from its signaling state FADH$^bullet$ to the inactive state FADH$^–$ (which reacts to the likewise inactive FAD) by means of the superoxide radical, O2$^$. We argue that the spin dynamics in the suggested reaction can act as a geomagnetic compass and that the very low physiological concentration (nM-$M) of otherwise toxic $^$ is sufficient, even favorable, for the biological function.

M3 - Journal article

VL - 96

SP - 4804

EP - 4813

JO - Biophysical Journal

JF - Biophysical Journal

SN - 0006-3495

ER -