Abstract
Abstract in English, Chinese The ability to navigate long distances is essential for many animals to locate shelter, food, and breeding grounds. Magnetic sense has evolved in various migratory and homing species to orient them based on the geomagnetic field. A highly conserved iron-sulfur cluster assembly protein IscA is proposed as an animal magnetoreceptor (MagR). Iron-sulfur cluster binding is also suggested to play an essential role in MagR magnetism and is thus critical in animal magnetoreception. In the current study, we provide evidence for distinct iron binding and iron-sulfur cluster binding in MagR in pigeons, an avian species that relies on the geomagnetic field for navigation and homing. Pigeon MagR showed significantly higher total iron content from both iron- and iron-sulfur binding. Y65 in pigeon MagR was shown to directly mediate mononuclear iron binding, and its mutation abolished iron-binding capacity of the protein. Surprisingly, both iron binding and iron-sulfur binding demonstrated synergistic effects, and thus appear to be integral and indispensable to pigeon MagR magnetism. These results not only extend our current understanding of the origin and complexity of MagR magnetism, but also imply a possible molecular explanation for the huge diversity in animal magnetoreception. 长距离的导航能力对许多动物来说至关重要，它们依赖这种能力寻找栖息地、食物和繁殖地。许多动物在漫长的进化中，逐渐演化出对微弱地磁场的感知能力，实现令人类惊叹的长距离导航和精准定位功能。其中的关键蛋白，动物磁受体MagR是一个高度保守的铁硫簇组装蛋白。在以往研究中，铁硫簇的结合被认为对MagR的磁性起着关键作用。该研究以鸽子MagR为例，证明了其同时结合铁和铁硫簇，且鸽子MagR的铁含量远高于其细菌同源蛋白IscA。Y65被鉴定为鸽子MagR的铁结合位点之一，对其进行突变则彻底丧失铁结合能力。尤为重要的是，我们还发现铁结合和铁硫簇结合两者对鸽子MagR的磁性缺一不可且协同作用。该研究为MagR的磁性起源提供了新的解释，扩展了我们对MagR磁学性质和生物指南针模型这一复杂系统的认知，也在分子水平上为对动物磁感应和生物导航的多样性提供了可能的解释。.