Phototrophic extracellular electron uptake is linked to carbon dioxide fixation in the bacterium Rhodopseudomonas palustris
Phototrophic extracellular electron uptake is linked to carbon dioxide fixation in the bacterium Rhodopseudomonas palustris
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DOI：
10.1038/s41467-019-09377-6
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发表时间：
2019-03-22
影响因子：
16.6
通讯作者：
Bose, Arpita
中科院分区：
文献类型：
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作者：
Guzman, Michael S.;Rengasamy, Karthikeyan;Bose, Arpita
细胞外电子摄取(EEU)是微生物从金属氧化物等固相导电物质中摄取电子的能力。EEU是由主要的光营养细菌属进行的，但对电子传递途径和生理电子汇知之甚少。在这里，我们展示了在光养细菌沼泽红假单胞菌Tie-1中，电子在EEU过程中进入光合作用电子传递链。阴极电子流也与高度还原的细胞内氧化还原环境相关。我们发现，还原当量用于二氧化碳(CO2)的固定，这是主要的电子吸收。Rubisco(Calvin-Benson-Bassham循环中的二氧化碳固定酶)编码基因的缺失会导致EEU降低90%。这项工作表明，光养生物可以直接利用固相导电物质进行电子转移、能量传递和固定二氧化碳。
Extracellular electron uptake (EEU) is the ability of microbes to take up electrons from solid-phase conductive substances such as metal oxides. EEU is performed by prevalent phototrophic bacterial genera, but the electron transfer pathways and the physiological electron sinks are poorly understood. Here we show that electrons enter the photosynthetic electron transport chain during EEU in the phototrophic bacterium Rhodopseudomonas palustris TIE-1. Cathodic electron flow is also correlated with a highly reducing intracellular redox environment. We show that reducing equivalents are used for carbon dioxide (CO2) fixation, which is the primary electron sink. Deletion of the genes encoding ruBisCO (the CO2-fixing enzyme of the Calvin-Benson-Bassham cycle) leads to a 90% reduction in EEU. This work shows that phototrophs can directly use solid-phase conductive substances for electron transfer, energy transduction, and CO2 fixation.