Outer Membrane c-Type Cytochromes OmcA and MtrC Play Distinct Roles in Enhancing the Attachment of Shewanella oneidensis MR-1 Cells to Goethite.
Outer Membrane c-Type Cytochromes OmcA and MtrC Play Distinct Roles in Enhancing the Attachment of Shewanella oneidensis MR-1 Cells to Goethite.
复制标题
外膜 c 型细胞色素 OmcA 和 MtrC 在增强 Shewanella oneidensis MR-1 细胞与针铁矿的附着方面发挥着独特的作用。
DOI：
10.1128/aem.01941-20
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发表时间：
2020
影响因子：
4.4
通讯作者：
Cai Peng
中科院分区：
文献类型：
--
作者：
Jing Xinxin;Wu Yichao;Shi Liang;Peacock Caroline L;Ashry Noha Mohamed;Gao Chunhui;Huang Qiaoyun;Cai Peng
外膜型细胞色素（c-Cyts）OmcA和MtrC是希瓦氏菌的关键末端还原酶，其直接将电子结合并转移至铁（氢）氧化物。虽然OmcA和MtrC在细胞表面的量和它们的分子结构在很大程度上是可比的，但已知MtrC在异化铁还原中发挥更重要的作用。为了探讨这些外膜细胞在希瓦氏菌MR-1与铁氧化物相互作用中的作用，研究了希瓦氏菌MR-1与铁氧化物的粘附过程。利用石英晶体微天平（QCM-D）对oneidensis MR-1野生型和C型细胞色素缺陷突变体（ΔomcA、ΔmtrC和ΔomcAΔ mtrC突变体）与针铁矿进行了比较。具有OmcA的菌株表现出快速的初始附着。QCM-D响应的定量模型表明，MtrC使细胞与针铁矿的接触面积和接触弹性分别提高了一倍以上和两倍以上，ATR-FTIR二维相关光谱（2D-CoS）分析表明，MtrC通过球内配位促进了初始界面反应.原子力显微镜（AFM）分析表明，OmcA增强细胞和针铁矿之间的吸引力约60%。因此，OmcA有助于更高的吸引力与针铁矿，并诱导快速的短期附着，而MtrC是更重要的，在长期的相互作用，通过增强的接触面积，这促进了界面反应。这些结果表明，c-Cyts OmcA和MtrC采用不同的机制来增强S的附着。将MR-1细胞转化为针铁矿。它提高了我们的理解外膜细胞的功能和细胞表面大分子的影响，在细胞-矿物质的相互作用。重要的是，希瓦氏菌是一组通用的和广泛的异化铁还原细菌，这是能够呼吸不溶性铁矿物质通过六个多血红素型细胞色素。外膜型细胞色素（c-Cyts）OmcA和MtrC是该途径中的末端还原酶，并且具有可比的蛋白质结构。在本研究中，我们阐明了OmcA和MtrC在S. oneidensis MR-1与针铁矿在全细胞水平上。OmcA赋予对针铁矿增强的亲和力并导致快速附着。同时，MtrC显著增加了细菌细胞与针铁矿的接触面积，促进了界面反应，这可能解释了其在细胞外电子传递中的核心作用。这项研究提供了新的见解细菌表面大分子在细菌与矿物的界面相互作用的作用，这是至关重要的细胞-矿物相互作用的全面理解的发展。
The outer membranec-type cytochromes (c-Cyts) OmcA and MtrC inShewanellaare key terminal reductases that bind and transfer electrons directly to iron (hydr)oxides. Although the amounts of OmcA and MtrC at the cell surface and their molecular structures are largely comparable, MtrC is known to play a more important role in dissimilatory iron reduction. To explore the roles of these outer membranec-Cyts in the interaction of Shewanella oneidensis MR-1 with iron oxides, the processes of attachment of S. oneidensis MR-1 wild type andc-type cytochrome-deficient mutants (the ΔomcA,ΔmtrC, and ΔomcAΔmtrCmutants) to goethite are compared via quartz crystal microbalance with dissipation monitoring (QCM-D). Strains with OmcA exhibit a rapid initial attachment. The quantitative model for QCM-D responses reveals that MtrC enhances the contact area and contact elasticity of cells with goethite by more than one and two times, respectively.In situattenuated total reflectance Fourier transform infrared two-dimensional correlation spectroscopic (ATR-FTIR 2D-CoS) analysis shows that MtrC promotes the initial interfacial reaction via an inner-sphere coordination. Atomic force microscopy (AFM) analysis demonstrates that OmcA enhances the attractive force between cells and goethite by about 60%. As a result, OmcA contributes to a higher attractive force with goethite and induces a rapid short-term attachment, while MtrC is more important in the longer-term interaction through an enhanced contact area, which promotes interfacial reactions. These results reveal thatc-Cyts OmcA and MtrC adopt different mechanisms for enhancing the attachment of S. oneidensis MR-1 cells to goethite. It improves our understanding of the function of outer membranec-Cyts and the influence of cell surface macromolecules in cell-mineral interactions.IMPORTANCEShewanellaspecies are one group of versatile and widespread dissimilatory iron-reducing bacteria, which are capable of respiring insoluble iron minerals via six multihemec-type cytochromes. Outer membranec-type cytochromes (c-Cyts) OmcA and MtrC are the terminal reductases in this pathway and have comparable protein structures. In this study, we elucidate the different roles of OmcA and MtrC in the interaction of S. oneidensis MR-1 with goethite at the whole-cell level. OmcA confers enhanced affinity toward goethite and results in rapid attachment. Meanwhile, MtrC significantly increases the contact area of bacterial cells with goethite and promotes the interfacial reaction, which may explain its central role in extracellular electron transfer. This study provides novel insights into the role of bacterial surface macromolecules in the interfacial interaction of bacteria with minerals, which is critical to the development of a comprehensive understanding of cell-mineral interactions.