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Spatially Resolved Chemical Analysis of Geobacter sulfurreducens Cell Surface.
ACS Nano ( IF 15.8 ) Pub Date : 2019-04-03 00:00:00 , DOI: 10.1021/acsnano.9b02032
Nikolai Lebedev 1 , Rhonda M Stroud 2 , Matthew D Yates 1 , Leonard Martin Tender 1
Affiliation  

Geobacter sulfurreducens is of interest for the highest efficiency of power generation and extremely long extracellular electron transfer (EET) between the bacterium and electrodes. Despite more than 15 years of intensive molecular biological research, there is still no clear answer which molecules are responsible for these processes. In the present work, we look at the problem from another (atomic) perspective and identify the location and shape of the compounds that are known to be conductive, particularly those containing Fe atoms. By using highly sophisticated energy dispersive X-ray spectroscopy combined with high-angle annular dark-field transmission electron microscopy enabling detection, identification, and localization of chemical compounds on the surface at nearly atomic spatial resolution, we analyze Fe spatial distribution within the G. sulfurreducens community. We discover the presence of small Fe-containing particles on the surface of the bacterium cells. The size of the particles (diameter 5.6 nm) is highly reproducible and comparable with the size of a single protein. The particles cover about 2% of the cell surface, which is similar to that expected for molecular conductors responsible for electron transfer through the bacterium cell wall. We find that G. sulfurreducens filaments (“bacterial molecular wires”) also contain Fe atoms in their bundles. We observe that the bacterium enable changing the distance between the Fe-containing bundles in the filaments from separated to attached (the latter is needed for the efficient electron transfer between the Fe-containing particles), depending on the bacterium metabolic activity and attachment to extracellular substrates. These results are consistent with the recently published research about the role of Fe atoms in protein molecular conductance ( Phys. Chem. Chem. Phys., 2018, 20, 14072−14081) and show what type of Fe-containing particles are involved in the bacterial extracellular communication. They can be used for the design and construction of artificial biomolecular wires and bioinorganic interfaces.

中文翻译:

减少土壤杆菌的细胞表面的空间分辨化学分析。

还原杆菌细菌和电极之间的最高发电效率和极长的细胞外电子转移(EET)引起了人们的关注。尽管进行了超过15年的深入分子生物学研究,但尚不清楚哪个分子负责这些过程。在当前的工作中,我们从另一个(原子)角度研究问题,并确定已知导电的化合物的位置和形状,特别是那些含Fe原子的化合物。通过使用高度复杂的能量色散X射线光谱技术与高角度环形暗场透射电子显微镜相结合,能够以接近原子的空间分辨率对化合物进行检测,识别和定位,我们分析了Fe中的Fe空间分布G.硫还原菌群落。我们发现细菌细胞表面上存在小的含铁颗粒。颗粒的大小(直径5.6 nm)具有很高的重现性,可与单个蛋白质的大小相媲美。颗粒覆盖约2%的细胞表面,这与负责通过细菌细胞壁进行电子转移的分子导体所预期的相似。我们发现G. sulfreducens细丝(“细菌分子丝”)在其束中还包含Fe原子。我们观察到,细菌能够改变细丝中含铁束之间的距离,从分离到附着(后者对于含铁颗粒之间的有效电子转移是必需的),这取决于细菌的代谢活性和对细胞外的附着基材。这些结果与对Fe原子的蛋白质分子传导中的作用(最近发表的研究结果一致,物理学,化学,化学物理。201820(14072−14081),并显示细菌胞外通讯涉及哪种类型的含铁颗粒。它们可用于人造生物分子线和生物无机界面的设计和构建。
更新日期:2019-04-03
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