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Maeda K, Naito Y. Dynamics of flavin containing radical pairs in SDS micellar media probed by static and pulse magnetic field effect and pulse ADMR. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1580779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Kiminori Maeda
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Yusuke Naito
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
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2
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Bajuszova Z, Naif H, Ali Z, McGinnis J, Islam M. Cavity enhanced liquid-phase stopped-flow kinetics. Analyst 2018; 143:493-502. [PMID: 29271423 DOI: 10.1039/c7an01823a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first application of liquid-phase broadband cavity enhanced spectroscopy (BBCEAS) to the measurement of stopped-flow kinetics is reported. The stopped-flow technique is widely used for the study of the kinetics of fast liquid-phase reactions down to millisecond timescales. UV-visible absorption spectroscopy is commonly used as the detection method. Increased sensitivity can potentially allow reactions which are too fast to be measured, to be studied by slowing down the reaction rate through the use of lower concentration of reactants. A simple low cost BBCEAS experimental setup was coupled to a commercial stopped-flow instrument. Comparative standard absorption measurements were also made using a UV-visible double-beam spectrometer as the detector. Measurements were made on the reaction of potassium ferricyanide with sodium ascorbate under pseudo-first order conditions at pH 8 and pH 9.2 A cavity enhancement factor (CEF) of 78 at 434 nm was obtained whilst the minimum detectable change in the absorption coefficient αmin(t), was 1.35 × 10-5 cm-1 Hz-1/2. The kinetic data at pH 9.2 was too fast to be measured using conventional spectroscopy, whilst the BBCEAS measurements allowed 30 fold lower concentration of reactants to be used which slowed down the reaction rate enough to allow the rate constant to be determined. The BBCEAS results showed a 58 fold improvement in sensitivity over the conventional measurements and also compared favourably with the relatively few previous liquid-phase cavity enhanced kinetic studies which have been performed using significantly more complex and expensive experimental setups.
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Affiliation(s)
- Zuzana Bajuszova
- School of Science and Engineering, Teesside University, Borough Road, Middlesbrough, TS1 3BA, UK.
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3
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Zollitsch TM, Jarocha LE, Bialas C, Henbest KB, Kodali G, Dutton PL, Moser CC, Timmel CR, Hore PJ, Mackenzie SR. Magnetically Sensitive Radical Photochemistry of Non-natural Flavoproteins. J Am Chem Soc 2018; 140:8705-8713. [PMID: 29940116 DOI: 10.1021/jacs.8b03104] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It is a remarkable fact that ∼50 μT magnetic fields can alter the rates and yields of certain free-radical reactions and that such effects might be the basis of the light-dependent ability of migratory birds to sense the direction of the Earth's magnetic field. The most likely sensory molecule at the heart of this chemical compass is cryptochrome, a flavin-containing protein that undergoes intramolecular, blue-light-induced electron transfer to produce magnetically sensitive radical pairs. To learn more about the factors that control the magnetic sensitivity of cryptochromes, we have used a set of de novo designed protein maquettes that self-assemble as four-α-helical proteins incorporating a single tryptophan residue as an electron donor placed approximately 0.6, 1.1, or 1.7 nm away from a covalently attached riboflavin as chromophore and electron acceptor. Using a specifically developed form of cavity ring-down spectroscopy, we have characterized the photochemistry of these designed flavoprotein maquettes to determine the identities and kinetics of the transient radicals responsible for the magnetic field effects. Given the gross structural and dynamic differences from the natural proteins, it is remarkable that the maquettes show magnetic field effects that are so similar to those observed for cryptochromes.
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Affiliation(s)
- Tilo M Zollitsch
- Department of Chemistry , University of Oxford, Physical and Theoretical Chemistry Laboratory , Oxford OX1 3QZ , United Kingdom
| | - Lauren E Jarocha
- Department of Chemistry , University of Oxford, Physical and Theoretical Chemistry Laboratory , Oxford OX1 3QZ , United Kingdom
| | - Chris Bialas
- Johnson Research Foundation, Department of Biochemistry and Biophysics , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Kevin B Henbest
- Department of Chemistry , University of Oxford, Centre for Advanced Electron Spin Resonance, Inorganic Chemistry Laboratory , Oxford OX1 3QR , United Kingdom
| | - Goutham Kodali
- Johnson Research Foundation, Department of Biochemistry and Biophysics , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - P Leslie Dutton
- Johnson Research Foundation, Department of Biochemistry and Biophysics , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Christopher C Moser
- Johnson Research Foundation, Department of Biochemistry and Biophysics , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Christiane R Timmel
- Department of Chemistry , University of Oxford, Centre for Advanced Electron Spin Resonance, Inorganic Chemistry Laboratory , Oxford OX1 3QR , United Kingdom
| | - P J Hore
- Department of Chemistry , University of Oxford, Physical and Theoretical Chemistry Laboratory , Oxford OX1 3QZ , United Kingdom
| | - Stuart R Mackenzie
- Department of Chemistry , University of Oxford, Physical and Theoretical Chemistry Laboratory , Oxford OX1 3QZ , United Kingdom
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Sheppard DMW, Li J, Henbest KB, Neil SRT, Maeda K, Storey J, Schleicher E, Biskup T, Rodriguez R, Weber S, Hore PJ, Timmel CR, Mackenzie SR. Millitesla magnetic field effects on the photocycle of an animal cryptochrome. Sci Rep 2017; 7:42228. [PMID: 28176875 PMCID: PMC5296725 DOI: 10.1038/srep42228] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/06/2017] [Indexed: 11/09/2022] Open
Abstract
Drosophila have been used as model organisms to explore both the biophysical mechanisms of animal magnetoreception and the possibility that weak, low-frequency anthropogenic electromagnetic fields may have biological consequences. In both cases, the presumed receptor is cryptochrome, a protein thought to be responsible for magnetic compass sensing in migratory birds and a variety of magnetic behavioural responses in insects. Here, we demonstrate that photo-induced electron transfer reactions in Drosophila melanogaster cryptochrome are indeed influenced by magnetic fields of a few millitesla. The form of the protein containing flavin and tryptophan radicals shows kinetics that differ markedly from those of closely related members of the cryptochrome-photolyase family. These differences and the magnetic sensitivity of Drosophila cryptochrome are interpreted in terms of the radical pair mechanism and a photocycle involving the recently discovered fourth tryptophan electron donor.
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Affiliation(s)
- Dean M. W. Sheppard
- Department of Chemistry, University of Oxford, Physical & Theoretical Chemistry Laboratory, Oxford OX1 3QZ, United Kingdom
| | - Jing Li
- Department of Chemistry, University of Oxford, Physical & Theoretical Chemistry Laboratory, Oxford OX1 3QZ, United Kingdom
| | - Kevin B. Henbest
- Department of Chemistry, University of Oxford, Physical & Theoretical Chemistry Laboratory, Oxford OX1 3QZ, United Kingdom
- Department of Chemistry, University of Oxford, Centre for Advanced Electron Spin Resonance, Inorganic Chemistry Laboratory, Oxford OX1 3QR, United Kingdom
| | - Simon R. T. Neil
- Department of Chemistry, University of Oxford, Physical & Theoretical Chemistry Laboratory, Oxford OX1 3QZ, United Kingdom
| | - Kiminori Maeda
- Department of Chemistry, University of Oxford, Centre for Advanced Electron Spin Resonance, Inorganic Chemistry Laboratory, Oxford OX1 3QR, United Kingdom
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570, Japan
| | - Jonathan Storey
- Department of Chemistry, University of Oxford, Centre for Advanced Electron Spin Resonance, Inorganic Chemistry Laboratory, Oxford OX1 3QR, United Kingdom
| | - Erik Schleicher
- Institute of Physical Chemistry, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Till Biskup
- Institute of Physical Chemistry, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Ryan Rodriguez
- Institute of Physical Chemistry, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Stefan Weber
- Institute of Physical Chemistry, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - P. J. Hore
- Department of Chemistry, University of Oxford, Physical & Theoretical Chemistry Laboratory, Oxford OX1 3QZ, United Kingdom
| | - Christiane R. Timmel
- Department of Chemistry, University of Oxford, Centre for Advanced Electron Spin Resonance, Inorganic Chemistry Laboratory, Oxford OX1 3QR, United Kingdom
| | - Stuart R. Mackenzie
- Department of Chemistry, University of Oxford, Physical & Theoretical Chemistry Laboratory, Oxford OX1 3QZ, United Kingdom
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Dodson CA, Wedge CJ, Murakami M, Maeda K, Wallace MI, Hore PJ. Fluorescence-detected magnetic field effects on radical pair reactions from femtolitre volumes. Chem Commun (Camb) 2015; 51:8023-6. [PMID: 25865161 DOI: 10.1039/c5cc01099c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We show that the effects of applied magnetic fields on radical pair reactions can be sensitively measured from sample volumes as low as ∼100 femtolitres using total internal reflection fluorescence microscopy. Development of a fluorescence-based microscope method is likely to be a key step in further miniaturisation that will allow detection of magnetic field effects on single molecules.
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Affiliation(s)
- C A Dodson
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
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6
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Jeschke G. Topical review introduction. Mol Phys 2014. [DOI: 10.1080/00268976.2014.930989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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7
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Neil SRT, Li J, Sheppard DMW, Storey J, Maeda K, Henbest KB, Hore PJ, Timmel CR, Mackenzie SR. Broadband Cavity-Enhanced Detection of Magnetic Field Effects in Chemical Models of a Cryptochrome Magnetoreceptor. J Phys Chem B 2014; 118:4177-84. [DOI: 10.1021/jp500732u] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Simon R. T. Neil
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, United Kingdom
| | - Jing Li
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, United Kingdom
| | - Dean M. W. Sheppard
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, United Kingdom
| | - Jonathan Storey
- Department of Chemistry, Inorganic
Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, United Kingdom
| | - Kiminori Maeda
- Department of Chemistry, Inorganic
Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, United Kingdom
| | - Kevin B. Henbest
- Department of Chemistry, Inorganic
Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, United Kingdom
| | - P. J. Hore
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, United Kingdom
| | - Christiane R. Timmel
- Department of Chemistry, Inorganic
Chemistry Laboratory, University of Oxford, Oxford, OX1 3QR, United Kingdom
| | - Stuart R. Mackenzie
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, United Kingdom
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Evans EW, Dodson CA, Maeda K, Biskup T, Wedge CJ, Timmel CR. Magnetic field effects in flavoproteins and related systems. Interface Focus 2013; 3:20130037. [PMID: 24511388 PMCID: PMC3915827 DOI: 10.1098/rsfs.2013.0037] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Within the framework of the radical pair mechanism, magnetic fields may alter the rate and yields of chemical reactions involving spin-correlated radical pairs as intermediates. Such effects have been studied in detail in a variety of chemical systems both experimentally and theoretically. In recent years, there has been growing interest in whether such magnetic field effects (MFEs) also occur in biological systems, a question driven most notably by the increasing body of evidence for the involvement of such effects in the magnetic compass sense of animals. The blue-light photoreceptor cryptochrome is placed at the centre of this debate and photoexcitation of its bound flavin cofactor has indeed been shown to result in the formation of radical pairs. Here, we review studies of MFEs on free flavins in model systems as well as in blue-light photoreceptor proteins and discuss the properties that are crucial in determining the magnetosensitivity of these systems.
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Affiliation(s)
- Emrys W. Evans
- Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
| | - Charlotte A. Dodson
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Kiminori Maeda
- Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
| | - Till Biskup
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104 Freiburg, Germany
| | - C. J. Wedge
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Christiane R. Timmel
- Centre for Advanced Electron Spin Resonance, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK
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Sergey N, Verkhovlyuk V, Kalneus E, Korolev V, Melnikov A, Burdukov A, Stass D, Molin YN. Registration of radical anions of Al, Ga, In tris-8-oxyquinolinates by magnetosensitive and spectrally resolved recombination luminescence in benzene solutions. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.08.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Maeda K, Neil SRT, Henbest KB, Weber S, Schleicher E, Hore PJ, Mackenzie SR, Timmel CR. Following Radical Pair Reactions in Solution: A Step Change in Sensitivity Using Cavity Ring-Down Detection. J Am Chem Soc 2011; 133:17807-15. [DOI: 10.1021/ja206783t] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kiminori Maeda
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, OX1 3QR, U.K
- Centre for Advanced Electron Spin Resonance, University of Oxford, OX1 3QR, U.K
| | - Simon R. T. Neil
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford, OX1 3QZ, U.K
| | - Kevin B. Henbest
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, OX1 3QR, U.K
- Centre for Advanced Electron Spin Resonance, University of Oxford, OX1 3QR, U.K
| | - Stefan Weber
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104 Freiburg, Germany
| | - Erik Schleicher
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104 Freiburg, Germany
| | - P. J. Hore
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford, OX1 3QZ, U.K
| | - Stuart R. Mackenzie
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford, OX1 3QZ, U.K
| | - Christiane R. Timmel
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, OX1 3QR, U.K
- Centre for Advanced Electron Spin Resonance, University of Oxford, OX1 3QR, U.K
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11
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Softley T. New editor in spin resonance: Gunnar Jeschke. Mol Phys 2011. [DOI: 10.1080/00268976.2011.595617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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