Nature453, 387-390 (15 May 2008) | doi:10.1038/nature06834; Received 29 October 2007; Accepted 11 February 2008; Published online 30 April 2008
Chemical compass model of avian magnetoreception
Kiminori Maeda1,4, Kevin B. Henbest1,4, Filippo Cintolesi2, Ilya Kuprov2, Christopher T. Rodgers2, Paul A. Liddell3, Devens Gust3, Christiane R. Timmel1 & P. J. Hore2
Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, UK
Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, UK
Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA
Approximately 50 species, including birds, mammals, reptiles, amphibians, fish, crustaceans and insects, are known to use the Earth's magnetic field for orientation and navigation1. Birds in particular have been intensively studied, but the biophysical mechanisms that underlie the avian magnetic compass are still poorly understood. One proposal, based on magnetically sensitive free radical reactions2, 3, is gaining support4, 5, 6, 7, 8, 9, 10, 11 despite the fact that no chemical reaction in vitro has been shown to respond to magnetic fields as weak as the Earth's (50 T) or to be sensitive to the direction of such a field. Here we use spectroscopic observation of a carotenoid–porphyrin–fullerene model system to demonstrate that the lifetime of a photochemically formed radical pair is changed by application of 50 T magnetic fields, and to measure the anisotropic chemical response that is essential for its operation as a chemical compass sensor. These experiments establish the feasibility of chemical magnetoreception and give insight into the structural and dynamic design features required for optimal detection of the direction of the Earth's magnetic field.