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Magnetic field effects on radical pair reactions: estimation of B(1/2) for flavin-tryptophan radical pairs in cryptochromes
Magnetic field effects on the yields of radical pair reactions are often characterised by the “half-field” parameter, B(1/2), which encodes useful information on spin relaxation, radical recombination kinetics and electron-electron couplings as well as electron–nuclear hyperfine interactions. Here w...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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The Royal Society of Chemistry
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9811481/ https://www.ncbi.nlm.nih.gov/pubmed/36519379 http://dx.doi.org/10.1039/d2cp03793a |
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author | Wong, Siu Ying Benjamin, Philip Hore, P. J. |
author_facet | Wong, Siu Ying Benjamin, Philip Hore, P. J. |
author_sort | Wong, Siu Ying |
collection | PubMed |
description | Magnetic field effects on the yields of radical pair reactions are often characterised by the “half-field” parameter, B(1/2), which encodes useful information on spin relaxation, radical recombination kinetics and electron-electron couplings as well as electron–nuclear hyperfine interactions. Here we use a variety of spin dynamics simulation methods to estimate the hyperfine-only values of B(1/2) for the flavin-tryptophan radical pair, [FAD˙(−) TrpH˙(+)], thought to be the detector in the magnetic compass sense of migratory songbirds. The main findings are: (a) in the absence of fast recombination and spin relaxation, [FAD˙(−) TrpH˙(+)] radical pairs in solution and in the putative magnetoreceptor protein, cryptochrome, have B(1/2) ≈ 1.89 mT and 2.46 mT, respectively. (b) The widely used expression for B(1/2) due to Weller et al. (Chem. Phys. Lett, 1983, 96, 24–27) is only applicable to small, short-lived (∼5 ns), rapidly tumbling radical pairs in solution, and is quantitatively unreliable in the context of magnetoreception. (c) In the absence of molecular tumbling, the low-field effect for [FAD˙(−) TrpH˙(+)] is predicted to be abolished by the anisotropic components of the hyperfine interactions. Armed with the 2.46 mT “base value” for cryptochrome, measurements of B(1/2) can be used to understand the impact of spin relaxation on its performance as a magnetic compass sensor. |
format | Online Article Text |
id | pubmed-9811481 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | The Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-98114812023-01-20 Magnetic field effects on radical pair reactions: estimation of B(1/2) for flavin-tryptophan radical pairs in cryptochromes Wong, Siu Ying Benjamin, Philip Hore, P. J. Phys Chem Chem Phys Chemistry Magnetic field effects on the yields of radical pair reactions are often characterised by the “half-field” parameter, B(1/2), which encodes useful information on spin relaxation, radical recombination kinetics and electron-electron couplings as well as electron–nuclear hyperfine interactions. Here we use a variety of spin dynamics simulation methods to estimate the hyperfine-only values of B(1/2) for the flavin-tryptophan radical pair, [FAD˙(−) TrpH˙(+)], thought to be the detector in the magnetic compass sense of migratory songbirds. The main findings are: (a) in the absence of fast recombination and spin relaxation, [FAD˙(−) TrpH˙(+)] radical pairs in solution and in the putative magnetoreceptor protein, cryptochrome, have B(1/2) ≈ 1.89 mT and 2.46 mT, respectively. (b) The widely used expression for B(1/2) due to Weller et al. (Chem. Phys. Lett, 1983, 96, 24–27) is only applicable to small, short-lived (∼5 ns), rapidly tumbling radical pairs in solution, and is quantitatively unreliable in the context of magnetoreception. (c) In the absence of molecular tumbling, the low-field effect for [FAD˙(−) TrpH˙(+)] is predicted to be abolished by the anisotropic components of the hyperfine interactions. Armed with the 2.46 mT “base value” for cryptochrome, measurements of B(1/2) can be used to understand the impact of spin relaxation on its performance as a magnetic compass sensor. The Royal Society of Chemistry 2022-12-07 /pmc/articles/PMC9811481/ /pubmed/36519379 http://dx.doi.org/10.1039/d2cp03793a Text en This journal is © the Owner Societies https://creativecommons.org/licenses/by-nc/3.0/ |
spellingShingle | Chemistry Wong, Siu Ying Benjamin, Philip Hore, P. J. Magnetic field effects on radical pair reactions: estimation of B(1/2) for flavin-tryptophan radical pairs in cryptochromes |
title | Magnetic field effects on radical pair reactions: estimation of B(1/2) for flavin-tryptophan radical pairs in cryptochromes |
title_full | Magnetic field effects on radical pair reactions: estimation of B(1/2) for flavin-tryptophan radical pairs in cryptochromes |
title_fullStr | Magnetic field effects on radical pair reactions: estimation of B(1/2) for flavin-tryptophan radical pairs in cryptochromes |
title_full_unstemmed | Magnetic field effects on radical pair reactions: estimation of B(1/2) for flavin-tryptophan radical pairs in cryptochromes |
title_short | Magnetic field effects on radical pair reactions: estimation of B(1/2) for flavin-tryptophan radical pairs in cryptochromes |
title_sort | magnetic field effects on radical pair reactions: estimation of b(1/2) for flavin-tryptophan radical pairs in cryptochromes |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9811481/ https://www.ncbi.nlm.nih.gov/pubmed/36519379 http://dx.doi.org/10.1039/d2cp03793a |
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