Capturing structural intermediates in an animal-like cryptochrome photoreceptor by time-resolved crystallography
Journal
Science Advances
Journal Volume
11
Journal Issue
20
ISSN
2375-2548
Date Issued
2025-05-16
Author(s)
Hosokawa, Yuhei
Wang, Po-Hsun
Saft, Martin
Caramello, Nicolas
Engilberge, Sylvain
Franz-Badur, Sophie
Gusti Ngurah Putu, Eka Putra
Nakamura, Mai
Wu, Wen-Jin
Wu, Hsiang-Yi
Lee, Cheng-Chung
Huang, Wei-Cheng
Huang, Kai-Fa
Chang, Yao-Kai
Yang, Cheng-Han
Fong, Meng-Iao
Lin, Wei-Ting
Yang, Kai-Chun
Ban, Yuki
Imura, Tomoki
Kazuoka, Atsuo
Tanida, Eisho
Owada, Shigeki
Joti, Yasumasa
Tanaka, Rie
Tanaka, Tomoyuki
Kang, Jungmin
Luo, Fangjia
Tono, Kensuke
Kiontke, Stephan
Korf, Lukas
Umena, Yasufumi
Tosha, Takehiko
Bessho, Yoshitaka
Nango, Eriko
Iwata, So
Royant, Antoine
Tsai, Ming-Daw
Yamamoto, Junpei
Essen, Lars-Oliver
Abstract
Animal-like cryptochromes are photoreceptors that control circadian rhythm and signaling in many eukaryotes. Transient photoreduction of the cryptochrome flavin chromophore initiated signaling via a poorly understood mechanism. By serial femtosecond crystallography (SFX), we show that the photoreduction mechanism of Chlamydomonas reinhardtii cryptochrome involves three loci [carboxyl-terminal region, a transient protonation pathway, and flavin adenine dinucleotide (FAD)–binding site] acting in unison to accomplish three effects: radical pair stabilization, protonation of FAD radical, and formation of the signaling state. Using 19 time-resolved SFX snapshots between 10 nanoseconds and 233 milliseconds, we found that light-driven FAD•–/tyrosyl-373 radical pair (RP) formation primes α22 unfolding. Electron transfer–dependent protonation of aspartate-321 by tyrosine-373 is the epicenter of unfolding by disrupting salt bridges between α22 and the photolyase homology region. Before helix unfolding, another pathway opens transiently for FAD•– protonation and RP stabilization. This link between RP formation and conformational changes provides a structural basis for signaling by animal-like cryptochromes.
Publisher
American Association for the Advancement of Science (AAAS)
Type
journal article