TEM and STEM-EDS evaluation of metal nanoparticle encapsulation in GroEL/GroES complexes according to the reaction mechanism of chaperonin
TEM and STEM-EDS evaluation of metal nanoparticle encapsulation in GroEL/GroES complexes according to the reaction mechanism of chaperonin
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根据伴侣蛋白的反应机理对 GroEL/GroES 复合物中金属纳米颗粒的封装进行 TEM 和 STEM-EDS 评估
DOI：
10.1093/jmicro/dfaa064
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发表时间：
2020
期刊：
影响因子：
1.8
通讯作者：
Koike-Takeshita* Ayumi
中科院分区：
文献类型：
--
作者：
Yoda Hiromi;Koike-Takeshita* Ayumi
大肠埃希氏菌Chaperonin GroEL是一种大的圆柱形蛋白质复合物，包含两个中心具有4.5 nm空腔的七聚体环，在GroES和三磷酸腺苷（ATP）的帮助下有助于细胞内蛋白质折叠。在这里，我们研究了GroEL也可以在GroES和ATP的帮助下将直径高达105 nm的金属纳米颗粒（NP）封装到空腔中的可能性。缓慢ATP水解的GroELD 52 A/D398 A突变体与GroES形成极其稳定的复合物（半衰期为1.6天），使得分析含有金属NP的GroEL/GroES复合物成为可能。扫描透射电子显微镜-能量色散X射线光谱分析清楚地证明了FePt NPs和Au NPs被封装在GroEL/GroES复合物中。动态光散射测量显示，GroEL/GroES复合物中的NP能够在溶液中保持其稳定性。我们先前描述了在ATP·BeFx和腺苷二磷酸·BeFx存在下孵育GroEL和GroES分别导致形成对称的足球形和不对称的子弹形复合物。基于这些知识，我们成功构建了足球形复合物，其中两个隔室被Pt或Au NP（第一隔室）和FePt NP（第二隔室）占据。该研究表明，金属纳米颗粒根据GroEL反应以逐步的方式依次包封。鉴于这些结果，伴侣蛋白可用作处理纳米材料的工具。
Escherichia colichaperonin GroEL, which is a large cylindrical protein complex comprising two heptameric rings with cavities of 4.5 nm each in the center, assists in intracellular protein folding with the aid of GroES and adenosine triphosphate (ATP). Here, we investigated the possibility that GroEL can also encapsulate metal nanoparticles (NPs) up to ∼5 nm in diameter into the cavities with the aid of GroES and ATP. The slow ATP-hydrolyzing GroELD52A/D398Amutant, which forms extremely stable complexes with GroES (half-time of ∼6 days), made it possible to analyze GroEL/GroES complexes containing metal NPs. Scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy analysis proved distinctly that FePt NPs and Au NPs were encapsulated in the GroEL/GroES complexes. Dynamic light scattering measurements showed that the NPs in the GroEL/GroES complex were able to maintain their dispersibility in solution. We previously described that the incubation of GroEL and GroES in the presence of ATP·BeFx and adenosine diphosphate·BeFx resulted in the formation of symmetric football-shaped and asymmetric bullet-shaped complexes, respectively. Based on this knowledge, we successfully constructed the football-shaped complex in which two compartments were occupied by Pt or Au NPs (first compartment) and FePt NPs (second compartment). This study showed that metal NPs were sequentially encapsulated according to the GroEL reaction in a step-by-step manner. In light of these results, chaperonin can be used as a tool for handling nanomaterials.