Electron uptake by iron-oxidizing phototrophic bacteria
Electron uptake by iron-oxidizing phototrophic bacteria
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DOI：
10.1038/ncomms4391
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发表时间：
2014-02-01
影响因子：
16.6
通讯作者：
Girguis, P. R.
中科院分区：
文献类型：
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作者：
Bose, A.;Gardel, E. J.;Girguis, P. R.
氧化还原反应是几乎所有生命形式能量产生的基础。尽管大多数生物体使用可溶性氧化剂和还原剂，但一些微生物可以通过细胞外电子转移获取固相材料作为电子受体或供体。许多研究都集中在固相氧化剂的还原上。人们对通过微生物细胞外电子转移吸收电子的了解知之甚少，并且对相关机制几乎一无所知。在这里，我们展示了铁氧化光合自养生物沼泽红假单胞菌 TIE-1 接受来自平衡电极的电子，二氧化碳作为唯一的碳源/电子受体。电子摄取和 ruBisCo I 型表达均受光刺激。电子吸收也发生在黑暗中，与光合作用无关。值得注意的是，pioABC 操纵子编码通过亚铁氧化进行光合自养生长所必需的蛋白质系统，它会影响电子吸收。这些数据揭示了光铁营养细胞利用细胞外电子转移进行电子摄取的先前未知的代谢多功能性。
Oxidation-reduction reactions underlie energy generation in nearly all life forms. Although most organisms use soluble oxidants and reductants, some microbes can access solid-phase materials as electron-acceptors or -donors via extracellular electron transfer. Many studies have focused on the reduction of solid-phase oxidants. Far less is known about electron uptake via microbial extracellular electron transfer, and almost nothing is known about the associated mechanisms. Here we show that the iron-oxidizing photoautotroph Rhodopseudomonas palustris TIE-1 accepts electrons from a poised electrode, with carbon dioxide as the sole carbon source/electron acceptor. Both electron uptake and ruBisCo form I expression are stimulated by light. Electron uptake also occurs in the dark, uncoupled from photosynthesis. Notably, the pioABC operon, which encodes a protein system essential for photoautotrophic growth by ferrous iron oxidation, influences electron uptake. These data reveal a previously unknown metabolic versatility of photoferrotrophs to use extracellular electron transfer for electron uptake.