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A Compass at Weak Magnetic Fields Using Thymine Dimer Repair

Zwang, Theodore J. and Tse, Edmund C. M. and Zhong, Dongping and Barton, Jacqueline K. (2018) A Compass at Weak Magnetic Fields Using Thymine Dimer Repair. ACS Central Science, 4 (3). pp. 405-412. ISSN 2374-7943. PMCID PMC5879481. doi:10.1021/acscentsci.8b00008.

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How birds sense the variations in Earth’s magnetic field for navigation is poorly understood, although cryptochromes, proteins homologous to photolyases, have been proposed to participate in this magnetic sensing. Here, in electrochemical studies with an applied magnetic field, we monitor the repair of cyclobutane pyrimidine dimer lesions in duplex DNA by photolyase, mutants of photolyase, and a modified cryptochrome. We find that the yield of dimer repair is dependent on the strength and angle of the applied magnetic field even when using magnetic fields weaker than 1 gauss. This high sensitivity to weak magnetic fields depends upon a fast radical pair reaction on the thymines leading to repair. These data illustrate chemically how cyclobutane pyrimidine dimer repair may be used in a biological compass informed by variations in Earth’s magnetic field.

Item Type:Article
Related URLs:
URLURL TypeDescription Information CentralArticle
Zwang, Theodore J.0000-0002-6815-4482
Tse, Edmund C. M.0000-0002-9313-1290
Barton, Jacqueline K.0000-0001-9883-1600
Additional Information:© 2018 American Chemical Society. This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. Received: January 4, 2018; Publication Date (Web): March 7, 2018. We are grateful to the NIH (GM061077 to J.K.B. and GM074813 to D.Z.) for their financial support. E.C.M.T. appreciates the Croucher Foundation for a postdoctoral fellowship. T.J.Z. is an NSF fellow (DGE-1144469) and would like to thank them for financial support of this research. We thank Jennifer Buz and Joseph Kirschvink for discussion and aid with SQUID measurements. We thank Mona Shahgholi and the Caltech MultiUser Mass Spectrometry Lab for help conducting mass spectrometry experiments. We dedicate this manuscript to Nicholas J. Turro, whose studies on radical pair reactions in weak fields stimulated this work. Author Contributions: T.J.Z. and J.K.B. designed the experiments. T.J.Z. performed most of the experiments. E.C.M.T. performed gel shift experiments, some electrochemistry experiments, DNA digestion, HPLC, and MS product analysis. D.Z. produced and purified all proteins as well as provided guidance for proper protein handling. T.J.Z. and J.K.B. wrote the manuscript. The authors declare no competing financial interest.
Funding AgencyGrant Number
Croucher FoundationUNSPECIFIED
NSF Graduate Research FellowshipDGE-1144469
Issue or Number:3
PubMed Central ID:PMC5879481
Record Number:CaltechAUTHORS:20180312-100907248
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Official Citation:A Compass at Weak Magnetic Fields Using Thymine Dimer Repair Theodore J. Zwang, Edmund C. M. Tse, Dongping Zhong, and Jacqueline K. Barton ACS Central Science 2018 4 (3), 405-412 DOI: 10.1021/acscentsci.8b00008
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85243
Deposited By: Tony Diaz
Deposited On:12 Mar 2018 17:20
Last Modified:15 Mar 2022 20:49

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