Hong Gongyi, Pachter Ruth
Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio, 45433, USA.
Eur Biophys J. 2023 Feb;52(1-2):27-37. doi: 10.1007/s00249-023-01630-7. Epub 2023 Feb 16.
Although the magnetosensitivity to weak magnetic fields, such as the geomagnetic field, which was exhibited by radical pairs that are potentially responsible for avian navigation, has been previously investigated by spin dynamics simulations, understanding this behavior for proposed radical pairs in other species is limited. These include, for example, radical pairs formed in the single-cell green alga Chlamydomonas reinhardtii (CraCRY) and in Columba livia (ClCRY4). In addition, the radical pair of FADH with the one-electron reduced cyclobutane thymine dimer that was shown to be sensitive to weak magnetic fields has been of interest. In this work, we investigated the directional magnetosensitivity of these radical pairs to a weak magnetic field by spin dynamics simulations. We find significant reduction in the magnetosensitivity by inclusion of dipolar and exchange interactions, which can be mitigated by a scavenging radical, as demonstrated for the [FAD TyrD] radical pair in CraCRY, but not for the [FADH T□T] radical pair because of the large exchange coupling. The directional magnetosensitivity of the ClCRY4 [FAD TyrE] radical pair can survive this adverse effect even without the scavenging reaction, possibly motivating further experimental exploration.
尽管之前通过自旋动力学模拟研究了自由基对表现出的对弱磁场（如地磁场）的磁敏感性，而这种磁敏感性可能与鸟类导航有关，但对于其他物种中提出的自由基对的这种行为的理解仍然有限。例如，这些物种包括单细胞绿藻莱茵衣藻（CraCRY）和家鸽（ClCRY4）中形成的自由基对。此外，已证明对弱磁场敏感的FADH与单电子还原的环丁烷胸腺嘧啶二聚体形成的自由基对也备受关注。在这项工作中，我们通过自旋动力学模拟研究了这些自由基对在弱磁场中的定向磁敏感性。我们发现，通过包含偶极和交换相互作用，磁敏感性会显著降低，对于CraCRY中的[FAD TyrD]自由基对，这种降低可以通过清除自由基来缓解，但对于[FADH T□T]自由基对则不行，因为其交换耦合较大。即使没有清除反应，ClCRY4 [FAD TyrE]自由基对的定向磁敏感性也能在这种不利影响下存活，这可能促使进一步的实验探索。
