Structural insights into photoactivation of plant Cryptochrome-2

• Published in: Communications biology Vol. 4; no. 1; p. 28
• Main Authors: Palayam, Malathy, Ganapathy, Jagadeesan, Guercio, Angelica M, Tal, Lior, Deck, Samuel L, Shabek, Nitzan
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 04.01.2021; Springer Nature; Nature Publishing Group UK; Nature Portfolio
• Subjects: Adenine; Amino Acid Sequence; Arabidopsis; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - metabolism; Arabidopsis Proteins - radiation effects; BASIC BIOLOGICAL SCIENCES; Biology; Chromophores; Circadian rhythms; Cryptochromes; Cryptochromes - chemistry; Cryptochromes - metabolism; Cryptochromes - radiation effects; Crystal structure; Entrainment; Flavin; Flavin-adenine dinucleotide; Flavin-Adenine Dinucleotide - metabolism; Flowering; Oligomerization; Photoactivation; Photoreceptors; Protein Structure, Quaternary; Seed germination
• ISSN: 2399-3642; 2399-3642
• DOI: 10.1038/s42003-020-01531-x

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 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 distinct 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.