Université Paris VI, 4 Place Jussieu, 75005 Paris, France.
J Biol Chem. 2011 Jun 17;286(24):21033-40. doi: 10.1074/jbc.M111.228940. Epub 2011 Apr 5.
Cryptochromes are flavin-based photoreceptors occurring throughout the biological kingdom, which regulate growth and development in plants and are involved in the entrainment of circadian rhythms of both plants and animals. A number of recent theoretical works suggest that cryptochromes might also be the receptors responsible for the sensing of the magnetic field of the earth (e.g. in insects, migratory birds, or migratory fish). Cryptochromes undergo forward light-induced reactions involving electron transfer to excited state flavin to generate radical intermediates, which correlate with biological activity. Here, we give evidence of a mechanism for the reverse reaction, namely dark reoxidation of protein-bound flavin in Arabidopsis thaliana cryptochrome (AtCRY1) by molecular oxygen that involves formation of a spin-correlated FADH(•)-superoxide radical pair. Formation of analogous radical pairs in animal cryptochromes might enable them to function as magnetoreceptors.
隐花色素是一种存在于整个生物界的黄素基光受体，它调节植物的生长和发育，并参与植物和动物昼夜节律的同步。一些最近的理论工作表明，隐花色素也可能是负责感知地球磁场的受体（例如，在昆虫、候鸟或洄游鱼类中）。隐花色素经历正向光诱导反应，涉及电子转移到激发态黄素以产生自由基中间体，这与生物活性相关。在这里，我们给出了一种机制的证据，即拟南芥隐花色素（AtCRY1）中由分子氧介导的蛋白结合黄素的暗再氧化反应，该反应涉及形成自旋相关的 FADH(•)-超氧自由基对。在动物隐花色素中形成类似的自由基对可能使它们能够作为磁受体发挥作用。
