<br>剖析 Cryptochrome 和 Timeless 之间的相互作用揭示了光依赖性识别的基础,Biochemistry

当前位置： X-MOL 学术 › Biochemistry › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

剖析 Cryptochrome 和 Timeless 之间的相互作用揭示了光依赖性识别的基础
Biochemistry ( IF 2.9 ) Pub Date : 2024-01-31 , DOI: 10.1021/acs.biochem.3c00630
Connor M Schneps ₁ , Robert Dunleavy ₁ , Brian R Crane ₁

Affiliation

昼夜节律是由细胞自主转录-翻译反馈回路决定的，这些反馈回路会夹带环境刺激。在黑腹果蝇的模型生物钟中，时钟由主光传感器隐花色素（CRY）对核心振荡器蛋白 timeless （TIM）的光诱导降解设定。与 TIM 结合的 CRY 的冷冻电镜结构表明，在广泛的 CRY：TIM 界面中，TIM N 端与 CRY FAD 口袋结合，其中 FAD 和相关的磷酸盐结合环（PBL）发生大量重排。参与 CRY 结合的 TIM N 末端在亚型中变化，有助于果蝇适应不同的光照环境。在此，我们通过肽结合测定和脉冲偶极电子自旋共振（ESR）光谱证明，单独的 TIM N 末端肽表现出与 CRY 的光依赖性结合，并且相互作用的亲和力取决于起始蛋氨酸残基。模拟对光敏感度较低的变体的 TIM N 末端的延伸大大减少了与 CRY 的相互作用。与 CRY：TIM 复合物中的黄素重排偶联的 CRY 残基的取代对 CRY 光激活有显着影响。PBL 上 α8 上的 CRY 残基 Arg237、Asn253 和 Gln254 对 CRY 自抑制性 C 末端尾部（CTT）的释放和随后的 TIM 结合至关重要。CRY 的这些关键光响应元件在整个无脊椎动物的 I 型隐花色中都非常保守，但未被脊索动物和植物的隐花色保守，它们可能利用了独特的光激活机制。

"点击查看英文标题和摘要"

Dissecting the Interaction between Cryptochrome and Timeless Reveals Underpinnings of Light-Dependent Recognition

Circadian rhythms are determined by cell-autonomous transcription–translation feedback loops that entrain to environmental stimuli. In the model circadian clock of Drosophila melanogaster, 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.

更新日期：2024-01-31

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南