PDF(Pubmed)
Abstract：
Ferritin, a spherical protein shell assembled from 24 subunits, functions as an efficient iron storage and release system through its channels. Understanding how various chemicals affect the structural behavior of ferritin is crucial for unravelling the origins of iron-related diseases in living organisms including humans. In particular, the influence of chemicals on ferritin\'s dynamics and iron release is barely explored at the single-protein level. Here, by employing optical nanotweezers using double-nanohole (DNH) structures, we examined the effect of ascorbic acid (reducing reagent) and pH on individual ferritin\'s conformational dynamics. The dynamics of ferritin increased as the concentration of ascorbic acid approached saturation. At pH 2.0, ferritin exhibited significant structural fluctuations and eventually underwent a stepwise disassembly into fragments. This work demonstrated the disassembly pathway and kinetics of a single ferritin molecule in solution. We identified four critical fragments during its disassembly pathway, which are 22-mer, 12-mer, tetramer, and dimer subunits. Moreover, we present single-molecule evidence of the cooperative disassembly of ferritin. Interrogating ferritin\'s structural change in response to different chemicals holds importance for understanding their roles in iron metabolism, hence facilitating further development of medical treatments for its associated diseases.
摘要：
铁蛋白,由24个亚基组成的球形蛋白质壳，作为一个有效的铁储存和释放系统通过其渠道。了解各种化学物质如何影响铁蛋白的结构行为对于揭示包括人类在内的生物体中铁相关疾病的起源至关重要。特别是,化学物质对铁蛋白动力学和铁释放的影响在单蛋白水平上几乎没有探索。这里,通过使用双纳米孔（DNH）结构的光学纳米镊子，我们研究了抗坏血酸（还原剂）和pH对个体铁蛋白构象动力学的影响。随着抗坏血酸浓度接近饱和，铁蛋白的动力学增加。在pH2.0时，铁蛋白表现出明显的结构波动，并最终逐步分解为碎片。这项工作证明了溶液中单个铁蛋白分子的分解途径和动力学。我们在其拆解途径中确定了四个关键片段，是22-mer，12-mer,四聚体,和二聚体亚基。此外，我们提供了铁蛋白协同分解的单分子证据。探究铁蛋白响应不同化学物质的结构变化对于理解它们在铁代谢中的作用具有重要意义。从而促进其相关疾病的医学治疗的进一步发展。
