Synthesis of Iron Oxide Nanoparticles in Listeria innocua Dps (DNA-Binding Protein from Starved Cells): A Study with the Wild-Type Protein and a Catalytic Centre Mutant
Synthesis of Iron Oxide Nanoparticles in Listeria innocua Dps (DNA-Binding Protein from Starved Cells): A Study with the Wild-Type Protein and a Catalytic Centre Mutant
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DOI：
10.1002/chem.200901138
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发表时间：
2010-01-01
影响因子：
4.3
通讯作者：
Sangregorio, Claudio
中科院分区：
文献类型：
--
作者：
Ceci, Pierpaolo;Chiancone, Emilia;Sangregorio, Claudio
本文提出了一项对比分析，对比分析了生长在dna结合蛋白空腔中的氧化铁纳米颗粒的磁性，这些dna结合蛋白来自于饥饿的李斯特菌（Listeria innocua, LiDps）和缺乏催化氧化铁酶中心的LiDps-tm的三突变体。TEM图像以及静态和动态磁性和电子磁共振（EMR）测量显示，在应用的制备条件下，即碱性pH，高温（65℃），排除氧气和过氧化氢的存在，平均直径约为3nm的磁铁矿和/或磁铁矿纳米颗粒在LiDps和LiDps-tm的腔内矿化。由此形成的磁性纳米颗粒（MNPs）具有相似的磁性，在4.5 K以上具有超顺磁性和较大的磁各向异性。有趣的是，在EMR光谱中观察到半场的所有吸收，这可以被认为是MNPs量子行为的表现。这些结果表明，Dps蛋白有利于在分子簇和传统MNPs之间的界面上产生纳米磁铁，并且铁氧化酶中心的存在虽然提高了纳米颗粒形成的效率，但并不影响MNPs的性质和精细结构。重要的是，含有mnp的MNPs在HRTEM网格上的自组织表明，含有Dps的MNPs可以以有序的方式沉积在油表面。
A comparative analysis of the magnetic properties of iron oxide nanoparticles grown in the cavity of the DNA-binding protein from starved cells of the bacterium Listeria innocua, LiDps, and of its triple-mutant lacking the catalytic ferroxidase centre, LiDps-tm, is presented. TEM images and static and dynamic magnetic and electron magnetic resonance (EMR) measurements reveal that, under the applied preparation conditions, namely alkaline pH, high temperature (65 degrees C), exclusion of oxygen, and the presence of hydrogen peroxide, maghemite and/or magnetite nanoparticles with an average diameter of about 3 nm are mineralised inside the cavities of both LiDps and LiDps-tm. The magnetic nanoparticles (MNPs) thus formed show similar magnetic properties, with superparamagnetic behaviour above 4.5 K and a large magnetic anisotropy. Interestingly, in the EMR spectra ail absorption at half-field is observed, which call be considered as a manifestation of the quantum behaviour of the MNPs. These results indicate that Dps proteins call be advantageously used for the production of nanomagnets at the interface between molecular Clusters and traditional MNPs and that the presence of the ferroxidase centre, though increasing the efficiency of nanoparticle formation, does not affect the nature and fine structure of the MNPs. Importantly, the self-organisation of MNP-containing Dps on HRTEM grids suggests that Dps-enclosed MNPs can be deposited oil surfaces in ail ordered fashion.