Journal Article

Chemical and structural analysis of a photoactive vertebrate cryptochrome from pigeon

Green, Carla B., Zoltowski, Brian D., Chelliah, Yogarany, Jarocha, Lauren, Takahashi, Joseph S., Karki, Nischal, Hibbs, Ryan E., Hore, Peter J., Xu, Wei, Wickramaratne, Anushka, Mouritsen, Henrik

2019

Overview

Computational and biochemical studies implicate the blue-light sensor cryptochrome (CRY) as an endogenous light-dependent magnetosensor enabling migratory birds to navigate using the Earth’s magnetic field. Validation of such a mechanism has been hampered by the absence of structures of vertebrate CRYs that have functional photochemistry. Here we present crystal structures of Columba livia (pigeon) CRY4 that reveal evolutionarily conserved modifications to a sequence of Trp residues (Trp-triad) required for CRY photoreduction. In ClCRY4, the Trp-triad chain is extended to include a fourth Trp (W369) and a Tyr (Y319) residue at the protein surface that imparts an unusually high quantum yield of photoreduction. These results are consistent with observations of night migratory behavior in animals at low light levels and could have implications for photochemical pathways allowing magnetosensing.

• Publisher: National Academy of Sciences
• Subject: Amino Acid Sequence / Animal behavior / Animal Migration - physiology / Animals / BASIC BIOLOGICAL SCIENCES / Biochemistry / Biological Sciences / Birds / Columbidae - metabolism / Computer applications / Conserved sequence / cryptochromes / Cryptochromes - chemistry / Cryptochromes - metabolism / Crystal structure / Geomagnetic field / INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY / Light / Light levels / Magnetic Fields / magnetoreception / Migratory birds / Organic chemistry / photobiology / Photochemicals / Photochemistry / Photochemistry - methods / Photoreduction / Pigeons / Structural analysis / Structure-Activity Relationship / Vertebrates / Vertebrates - metabolism