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bioRxiv · 10.1101/2020.07.30.227371

Structural Insights into Photoactivation of Plant Cryptochrome-2

Palayam, M.·Ganapathy, J.·Guercio, A. M.·Tal, L.·Deck, S. L.·Shabek, N.
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Abstract

Cryptochromes (CRYs) are evolutionarily conserved photoreceptors that mediate various light-induced responses in bacteria, plants, and animals. Plant cryptochromes govern a variety of critical growth and developmental processes including seed germination, flowering time and entrainment of the circadian clock. CRYs photocycle involves reduction of their flavin adenine dinucleotide (FAD)-bound chromophore, which is completely oxidized in the dark and semi to fully reduced in the light signaling-active state. Despite the significant progress in characterizing cryptochromes, important aspects of their photochemistry, regulation, and light-induced structural changes remain to be addressed. In this study, we determine the crystal structure of the photosensory domain of Arabidopsis CRY2 in a tetrameric active state. Systematic structure-based analyses of photo-activated and inactive plant CRYs elucidate new structural elements and critical residues that dynamically partake in photo-induced oligomerization. Our study offers an updated model of CRYs photoactivation mechanism as well as the mode of its regulation by interacting proteins.

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Palayam, M., Ganapathy, J., Guercio, A. M., Tal, L., Deck, S. L., Shabek, N.. 2020-07-30. Structural Insights into Photoactivation of Plant Cryptochrome-2. https://doi.org/10.1101/2020.07.30.227371

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