Structural Insights into Photoactivation of Plant Cryptochrome-2

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 t...

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Bibliographic Details
Published inbioRxiv
Main Authors Palayam, Malathy, Jagadeesan Ganapathy, Guercio, Angelica M, Tal, Lior, Deck, Samuel L, Nitzan Shabek
Format Paper
LanguageEnglish
Published Cold Spring Harbor Cold Spring Harbor Laboratory Press 03.09.2020
Subjects
Adenine
Chromophores
Circadian rhythms
Cryptochromes
Crystal structure
Entrainment
Flavin
Flavin-adenine dinucleotide
Flowering
Oligomerization
Photoactivation
Seed germination
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Summary: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. CRY’s 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. Competing Interest Statement The authors have declared no competing interest.
DOI:10.1101/2020.07.30.227371