Institute of Molecular Physiology (IMP), Johannes Gutenberg-University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128, Mainz, Germany.
University of Cologne, Faculty of Mathematics and Natural Sciences, Institute of Biochemistry, Zülpicher Straße 47, 50674, Cologne, Germany.
Nat Commun. 2023 Oct 30;14(1):6918. doi: 10.1038/s41467-023-42708-2.
Cryptochromes (CRYs) are a structurally conserved but functionally diverse family of proteins that can confer unique sensory properties to organisms. In the marine bristle worm Platynereis dumerilii, its light receptive cryptochrome L-CRY (PdLCry) allows the animal to discriminate between sunlight and moonlight, an important requirement for synchronizing its lunar cycle-dependent mass spawning. Using cryo-electron microscopy, we show that in the dark, PdLCry adopts a dimer arrangement observed neither in plant nor insect CRYs. Intense illumination disassembles the dimer into monomers. Structural and functional data suggest a mechanistic coupling between the light-sensing flavin adenine dinucleotide chromophore, the dimer interface, and the C-terminal tail helix, with a likely involvement of the phosphate binding loop. Taken together, our work establishes PdLCry as a CRY protein with inverse photo-oligomerization with respect to plant CRYs, and provides molecular insights into how this protein might help discriminating the different light intensities associated with sunlight and moonlight.
隐花色素（CRYs）是一个结构保守但功能多样的蛋白质家族，它可以赋予生物体独特的感觉特性。在海洋多毛环节虫 Platynereis dumerilii 中，其光受体隐花色素 L-CRY（PdLCry）使动物能够区分阳光和月光，这是同步其月相依赖性大量繁殖的重要要求。使用冷冻电子显微镜，我们表明在黑暗中，PdLCry 采用了一种二聚体排列，这种排列既不在植物也不在昆虫 CRYs 中观察到。强烈的光照将二聚体分解为单体。结构和功能数据表明，光感应黄素腺嘌呤二核苷酸发色团、二聚体界面和 C 末端尾巴螺旋之间存在机械偶联，可能涉及磷酸结合环。总之，我们的工作确立了 PdLCry 作为一种与植物 CRYs 相反的光聚化 CRY 蛋白，并为该蛋白如何帮助区分与阳光和月光相关的不同光强提供了分子见解。
