Publication Date:
2019
Description:
〈p〉Cryptochromes are blue-light photoreceptor proteins, which provide input to circadian clocks. The cryptochrome from 〈i〉Drosophila melanogaster〈/i〉 (〈i〉Dm〈/i〉Cry) modulates the degradation of Timeless and itself. It is unclear how light absorption by the chromophore and the subsequent redox reactions trigger these events. Here, we use nano- to millisecond time-resolved x-ray solution scattering to reveal the light-activated conformational changes in 〈i〉Dm〈/i〉Cry and the related (6-4) photolyase. 〈i〉Dm〈/i〉Cry undergoes a series of structural changes, culminating in the release of the carboxyl-terminal tail (CTT). The photolyase has a simpler structural response. We find that the CTT release in 〈i〉Dm〈/i〉Cry depends on pH. Mutation of a conserved histidine, important for the biochemical activity of 〈i〉Dm〈/i〉Cry, does not affect transduction of the structural signal to the CTT. Instead, molecular dynamics simulations suggest that it stabilizes the CTT in the resting-state conformation. Our structural photocycle unravels the first molecular events of signal transduction in an animal cryptochrome.〈/p〉
Electronic ISSN:
2375-2548
Topics:
Natural Sciences in General
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