University of Bristol, Physics Department, HH Wills Physics Laboratory, Tyndall Avenues, Bristol, BS8 1TL, UK.
J Am Chem Soc. 2010 Mar 17;132(10):3621-7. doi: 10.1021/ja910918b.
Highly symmetrical protein cage architectures from three different iron storage proteins, heavy and light human ferritin chains (HuHFt and HuLFt) and ferritin from the hyperthemophilic bacterium Pyrococcus furiosus (PfFt), have been used as models for understanding the molecular basis of silver ion deposition and metal core formation inside the protein cavity. Biomineralization using protein cavities is an important issue for the fabrication of biometamaterials under mild synthetic conditions. Silver nanoparticles (AgNPs) were produced with high yields within PfFt but not within HuHFt and HuLFt. To explain the molecular basis of silver incorporation, the X-ray crystal structure of Ag-containing PfFt has been solved. This is the first structure of a silver containing ferritin reported to date, and it revealed the presence of specific binding and nucleation sites of Ag(I) that are not conserved in other ferritin templates. The AgNP encapsulated by PfFt were further characterized by the combined use of different physical-chemical techniques. These showed that the AgNPs are endowed with a narrow size distribution (2.1 +/- 0.4 nm), high stability in water solution at millimolar concentration, and high thermal stability. These properties make the AgNP obtained within PftFt exploitable for a range of applications, in fields as diverse as catalysis in water, preparation of metamaterials, and in vivo diagnosis and antibacterial or tumor therapy.
已使用来自三种不同铁储存蛋白（人重链铁蛋白和人轻链铁蛋白以及来自嗜热古菌 Pyrococcus furiosus 的铁蛋白）的高度对称蛋白笼结构作为模型，以了解银离子沉积和金属核心在蛋白腔内部形成的分子基础。使用蛋白腔进行生物矿化是在温和的合成条件下制造生物金属材料的一个重要问题。PfFt 中可高产生成银纳米颗粒（AgNPs），而 HuHFt 和 HuLFt 中则不行。为了解释银掺入的分子基础，已解析了含银 PfFt 的 X 射线晶体结构。这是迄今为止报道的第一个含银铁蛋白结构，它揭示了特定的 Ag(I)结合和成核位点的存在，这些位点在其他铁蛋白模板中不存在保守性。通过结合使用不同的物理化学技术，对 PfFt 包裹的 AgNP 进行了进一步的表征。这些结果表明，AgNPs 具有较窄的尺寸分布（2.1 +/- 0.4nm）、在毫摩尔浓度的水溶液中具有高稳定性和高热稳定性。这些特性使得在 PfFt 中获得的 AgNP 可用于广泛的应用领域，如水中的催化、超材料的制备、体内诊断以及抗菌或肿瘤治疗。
