Frederiksen Anders, Langebrake Corinna, Hanić Maja, Manthey Georg, Mouritsen Henrik, Liedvogel Miriam, Solov'yov Ilia A
Institute of Physics, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky Strasse 9-11, Oldenburg 26129, Germany.
Institute of Avian Research, An der Vogelwarte 21, Wilhelmshaven 26386, Germany.
ACS Omega. 2023 Jul 12;8(29):26425-26436. doi: 10.1021/acsomega.3c02963. eCollection 2023 Jul 25.
The ability of migratory birds to sense magnetic fields has been known for decades, although the understanding of the underlying mechanism is still elusive. Currently, the strongest magnetoreceptor candidate in birds is a protein called cryptochrome 4a. The cryptochrome 4a protein has changed through evolution, apparently endowing some birds with a more pronounced magnetic sensitivity than others. Using phylogenetic tools, we show that a specific tryptophan tetrad and a tyrosine residue predicted to be essential for cryptochrome activation are highly conserved in the avian clade. Through state-of-the-art molecular dynamics simulations and associated analyses, we also studied the role of these specific residues and the associated mutants on the overall dynamics of the protein. The analyses of the single residue mutations were used to judge how far a local change in the protein structure can impact specific dynamics of European robin cryptochrome 4a. We conclude that the replacements of each of the tryptophans one by one with a phenylalanine do not compromise the overall stability of the protein.
候鸟感知磁场的能力已为人所知数十年，尽管对其潜在机制的理解仍很模糊。目前，鸟类中最有力的磁受体候选蛋白是一种名为隐花色素4a的蛋白质。隐花色素4a蛋白在进化过程中发生了变化，显然赋予了一些鸟类比其他鸟类更显著的磁敏感性。利用系统发育工具，我们表明一个特定的色氨酸四联体和一个预计对隐花色素激活至关重要的酪氨酸残基在鸟类进化枝中高度保守。通过最先进的分子动力学模拟和相关分析，我们还研究了这些特定残基及其相关突变体对蛋白质整体动力学的作用。对单个残基突变的分析用于判断蛋白质结构的局部变化能在多大程度上影响欧洲知更鸟隐花色素4a的特定动力学。我们得出结论，将每个色氨酸逐一替换为苯丙氨酸不会损害蛋白质的整体稳定性。
