{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"omics_type":["Unknown"],"submitter":["Schneps CM"],"funding":["National Institute of General Medical Sciences","NIGMS NIH HHS","NIH HHS","National Science Foundation"],"pubmed_abstract":["Circadian rhythms are determined by cell-autonomous transcription-translation feedback loops that entrain to environmental stimuli. In the model circadian clock of <i>Drosophila melanogaster</i>, the clock is set by the light-induced degradation of the core oscillator protein timeless (TIM) by the principal light-sensor cryptochrome (CRY). The cryo-EM structure of CRY bound to TIM revealed that within the extensive CRY:TIM interface, the TIM N-terminus binds into the CRY FAD pocket, in which FAD and the associated phosphate-binding loop (PBL) undergo substantial rearrangement. The TIM N-terminus involved in CRY binding varies in isoforms that facilitate the adaptation of flies to different light environments. Herein, we demonstrate, through peptide binding assays and pulsed-dipolar electron spin resonance (ESR) spectroscopy, that the TIM N-terminal peptide alone exhibits light-dependent binding to CRY and that the affinity of the interaction depends on the initiating methionine residue. Extensions to the TIM N-terminus that mimic less light-sensitive variants have substantially reduced interactions with CRY. Substitutions of CRY residues that couple to the flavin rearrangement in the CRY:TIM complex have dramatic effects on CRY light activation. CRY residues Arg237 on α8, Asn253, and Gln254 on the PBL are critical for the release of the CRY autoinhibitory C-terminal tail (CTT) and subsequent TIM binding. These key light-responsive elements of CRY are well conserved throughout Type I cryptochromes of invertebrates but not by cryptochromes of chordates and plants, which likely utilize a distinct light-activation mechanism."],"journal":["Biochemistry"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC11289166"],"repository":["biostudies-literature"],"pubmed_title":["Dissecting the Interaction between Cryptochrome and Timeless Reveals Underpinnings of Light-Dependent Recognition."],"pmcid":["PMC11289166"],"funding_grant_id":["MCB2129728","R24 GM146107","P30 GM124166","P41 GM103521","R35 GM122535","R24GM146107","R35122535","S10 OD021543"],"pubmed_authors":["Crane BR","Dunleavy R","Schneps CM"],"additional_accession":[]},"is_claimable":false,"name":"Dissecting the Interaction between Cryptochrome and Timeless Reveals Underpinnings of Light-Dependent Recognition.","description":"Circadian rhythms are determined by cell-autonomous transcription-translation feedback loops that entrain to environmental stimuli. In the model circadian clock of <i>Drosophila melanogaster</i>, the clock is set by the light-induced degradation of the core oscillator protein timeless (TIM) by the principal light-sensor cryptochrome (CRY). The cryo-EM structure of CRY bound to TIM revealed that within the extensive CRY:TIM interface, the TIM N-terminus binds into the CRY FAD pocket, in which FAD and the associated phosphate-binding loop (PBL) undergo substantial rearrangement. The TIM N-terminus involved in CRY binding varies in isoforms that facilitate the adaptation of flies to different light environments. Herein, we demonstrate, through peptide binding assays and pulsed-dipolar electron spin resonance (ESR) spectroscopy, that the TIM N-terminal peptide alone exhibits light-dependent binding to CRY and that the affinity of the interaction depends on the initiating methionine residue. Extensions to the TIM N-terminus that mimic less light-sensitive variants have substantially reduced interactions with CRY. Substitutions of CRY residues that couple to the flavin rearrangement in the CRY:TIM complex have dramatic effects on CRY light activation. CRY residues Arg237 on α8, Asn253, and Gln254 on the PBL are critical for the release of the CRY autoinhibitory C-terminal tail (CTT) and subsequent TIM binding. These key light-responsive elements of CRY are well conserved throughout Type I cryptochromes of invertebrates but not by cryptochromes of chordates and plants, which likely utilize a distinct light-activation mechanism.","dates":{"release":"2024-01-01T00:00:00Z","publication":"2024 Jan","modification":"2026-07-02T03:21:36.622Z","creation":"2025-08-17T03:06:02.432Z"},"accession":"S-EPMC11289166","cross_references":{"pubmed":["38294880"],"doi":["10.1021/acs.biochem.3c00630"]}}