Alternative radical pairs for cryptochrome-based magnetoreception
Alternative radical pairs for cryptochrome-based magnetoreception
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DOI：
10.1098/rsif.2013.1063
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发表时间：
2014-06-06
影响因子：
3.9
通讯作者：
Hore, P. J.
中科院分区：
文献类型：
--
作者：
Lee, Alpha A.;Lau, Jason C. S.;Hore, P. J.
越来越多的证据表明，动物，特别是鸟类，感知地球磁场方向的非凡能力依赖于蛋白质隐色素的磁敏感光化学反应。一般认为，磁场作用于自由基对[FAD（中心点-）TrpH（中心点+）]，该自由基对是通过将电子从一组三个色氨酸残基转移到蛋白质内的光激发黄素腺嘌呤二核苷酸辅因子而形成的。在这里，我们研究了[FAD（中心点-）Z（中心点）]自由基对作为罗盘磁感受器的适用性，其中Z（中心点）是电子自旋与磁核（如氢和氮）没有超精细相互作用的自由基。量子自旋动力学模拟的反应性[FAD（中心点-）Z（中心点）]表明，它是两个数量级更敏感的地磁场的方向比[FAD（中心点-）TrpH（中心点+）]在相同的条件下（50 μ T的磁场，1 μ s的自由基寿命）。[FAD（中心点-）Z（中心点）]的有利磁性来自两个自由基之间的超精细相互作用的不对称分布和黄素自由基的接近最佳的磁性。最后，我们讨论的身份Z（中心点）和可能的路线，其形成的一部分，自旋相关的自由基对与FAD自由基隐花色素。
There is growing evidence that the remarkable ability of animals, in particular birds, to sense the direction of the Earth's magnetic field relies on magnetically sensitive photochemical reactions of the protein cryptochrome. It is generally assumed that the magnetic field acts on the radical pair [FAD(center dot-) TrpH(center dot+)] formed by the transfer of an electron from a group of three tryptophan residues to the photo-excited flavin adenine dinucleotide cofactor within the protein. Here, we examine the suitability of an [FAD(center dot-) Z(center dot)] radical pair as a compass magnetoreceptor, where Z(center dot) is a radical in which the electron spin has no hyperfine interactions with magnetic nuclei, such as hydrogen and nitrogen. Quantum spin dynamics simulations of the reactivity of [FAD(center dot-) Z(center dot)] show that it is two orders of magnitude more sensitive to the direction of the geomagnetic field than is [FAD(center dot-) TrpH(center dot+)] under the same conditions (50 mu T magnetic field, 1 mu s radical lifetime). The favourable magnetic properties of [FAD(center dot-) Z(center dot)] arise from the asymmetric distribution of hyperfine interactions among the two radicals and the near-optimal magnetic properties of the flavin radical. We close by discussing the identity of Z(center dot) and possible routes for its formation as part of a spin-correlated radical pair with an FAD radical in cryptochrome.