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Determination of Radical–Radical Distances in Light‐Active Proteins and Their Implication for Biological Magnetoreception
Author(s) -
Nohr Daniel,
Paulus Bernd,
Rodriguez Ryan,
Okafuji Asako,
Bittl Robert,
Schleicher Erik,
Weber Stefan
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201700389
Subject(s) - cryptochrome , magnetoreception , photolyase , flavin group , electron transfer , photochemistry , chemistry , biophysics , drosophila melanogaster , dna , dna repair , biology , biochemistry , enzyme , magnetic field , physics , earth's magnetic field , circadian clock , quantum mechanics , gene
Light‐generated short‐lived radial pairs have been suggested to play pivotal roles in cryptochromes and photolyases. Cryptochromes are very probably involved in magnetic compass sensing in migratory birds and the magnetic‐field‐dependent behavior of insects. We examined photo‐generated transient states in the cryptochrome of Drosophila melanogaster and in the structurally related DNA‐repair enzyme Escherichia coli DNA photolyase. Using pulsed EPR spectroscopy, the exchange and dipolar contributions to the electron spin–spin interaction were determined in a straightforward and direct way. With these parameters, radical‐pair partners may be identified and the magnetoreceptor efficiency of cryptochromes can be evaluated. We present compelling evidence for an extended electron‐transfer cascade in the Drosophila cryptochrome, and identified W394 as a key residue for flavin photoreduction and formation of a spin‐correlated radical pair with a sufficient lifetime for high‐sensitivity magnetic‐field sensing.