英国曼切斯特大学Richard A. Baines等研究人员合作揭示果蝇中自由基对磁感应的基本要素。相关论文于2023年2月22日在线发表在《自然》杂志上。

据研究人员介绍，许多动物利用地球的磁场（也称为地磁场）进行导航。最受欢迎的磁感应机制涉及黄素腺嘌呤二核苷酸（FAD）和光感受器蛋白CRYPTOCHROME（CRY）内的色氨酸残基链之间的蓝光激活电子转移反应。由此产生的自由基对的自旋状态，以及因此CRY在其活性状态下的浓度，受到地磁场的影响。然而，以CRY为中心的典型的自由基对机制并不能解释许多生理和行为观察。

利用电生理学和行为分析，研究人员在单神经元和生物体的水平上检测磁场反应。结果表明，黑腹果蝇CRY的52个C端氨基酸残基缺乏典型的FAD结合域和色氨酸链，但足以促进磁感受。研究人员还表明，增加细胞内的FAD可以增强蓝光诱导的和磁场依赖的对C端介导的活动的影响。仅仅高水平的FAD就足以引起蓝光神经元的敏感性，以及这种反应的增效作用，特别是在磁场存在的情况下。这些结果揭示了果蝇初级磁感受器的基本组成部分，并提供了强有力的证据，表明非经典（即非CRY依赖）的自由基对可以在细胞中引起磁场反应。

附：英文原文

Title: Essential elements of radical pair magnetosensitivity in Drosophila

Author: Bradlaugh, Adam A., Fedele, Giorgio, Munro, Anna L., Hansen, Celia Napier, Hares, John M., Patel, Sanjai, Kyriacou, Charalambos P., Jones, Alex R., Rosato, Ezio, Baines, Richard A.

Issue&Volume: 2023-02-22

Abstract: Many animals use Earth’s magnetic field (also known as the geomagnetic field) for navigation1. The favoured mechanism for magnetosensitivity involves a blue-light-activated electron-transfer reaction between flavin adenine dinucleotide (FAD) and a chain of tryptophan residues within the photoreceptor protein CRYPTOCHROME (CRY). The spin-state of the resultant radical pair, and therefore the concentration of CRY in its active state, is influenced by the geomagnetic field2. However, the canonical CRY-centric radical-pair mechanism does not explain many physiological and behavioural observations2,3,4,5,6,7,8. Here, using electrophysiology and behavioural analyses, we assay magnetic-field responses at the single-neuron and organismal levels. We show that the 52 C-terminal amino acid residues of Drosophila melanogaster CRY, lacking the canonical FAD-binding domain and tryptophan chain, are sufficient to facilitate magnetoreception. We also show that increasing intracellular FAD potentiates both blue-light-induced and magnetic-field-dependent effects on the activity mediated by the C terminus. High levels of FAD alone are sufficient to cause blue-light neuronal sensitivity and, notably, the potentiation of this response in the co-presence of a magnetic field. These results reveal the essential components of a primary magnetoreceptor in flies, providing strong evidence that non-canonical (that is, non-CRY-dependent) radical pairs can elicit magnetic-field responses in cells.

DOI: 10.1038/s41586-023-05735-z

Source: https://www.nature.com/articles/s41586-023-05735-z