The release of the C-terminal tail (CTT) of the Drosophila cryptochrome (dCry) upon illumination is central to light signal transduction in this flavin-containing photoreceptor, but the roles of flavin in the different ionic and protonation states are not fully understood. Here, the authors show that both flavin anionic semiquinone and anionic hydroquinone can trigger CTT release, while the formation of a small fraction of neutral semiquinone under neutral conditions, moderately supresses CTT release, but ensures fast recovery of dCry after light sensing.
- Wenlong Xie
- Mengqi Wan
- Lei Xu