A hydrogen-dependent geochemical analogue of primordial carbon and energy metabolism
A hydrogen-dependent geochemical analogue of primordial carbon and energy metabolism
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DOI：
10.1038/s41559-020-1125-6
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发表时间：
2020-03-02
影响因子：
16.8
通讯作者：
Martin, William F.
中科院分区：
文献类型：
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作者：
Preiner, Martina;Igarashi, Kensuke;Martin, William F.
氢气（H-2）是由碱性热液喷口通过一种称为蛇纹石化的古老地球化学过程产生的，在该过程中，水与地壳深处的含铁矿物发生反应。H-2是生物固定CO2的最古老和唯一的能量释放途径乙酰辅酶A途径的电子供体。在新陈代谢的起源，CO2固定的热液H-2蛇纹状系统内可能有之前和图案的生物途径。在这里，我们表明，三种热液矿物-硫铁矿（Fe 3S 4），磁铁矿（Fe 3 O 4）和铁镍铁矿（Ni 3Fe）-催化固定CO2与H-2在100 ℃下，在碱性水溶液条件下。产物谱包括甲酸盐（高达200 mM）、乙酸盐（高达100 μ M）、丙酮酸盐（高达10 μ M）、甲醇（高达100 μ M）和甲烷。研究结果揭示了现代热液喷口中微生物代谢的地球化学起源和非生物甲酸盐和甲烷合成的本质，并显示碱性热液喷口中发现的三种铁矿物在水中可将CO2和H-2转化为甲酸盐、乙酸盐和丙酮酸盐，表明这些反应可能为早期代谢铺平了道路。
Hydrogen gas, H-2, is generated by alkaline hydrothermal vents through an ancient geochemical process called serpentinization, in which water reacts with iron-containing minerals deep within the Earth's crust. H-2 is the electron donor for the most ancient and the only energy-releasing route of biological CO2 fixation, the acetyl-CoA pathway. At the origin of metabolism, CO2 fixation by hydrothermal H-2 within serpentinizing systems could have preceded and patterned biotic pathways. Here we show that three hydrothermal minerals-greigite (Fe3S4), magnetite (Fe3O4) and awaruite (Ni3Fe)-catalyse the fixation of CO2 with H-2 at 100 degrees C under alkaline aqueous conditions. The product spectrum includes formate (up to 200 mM), acetate (up to 100 mu M), pyruvate (up to 10 mu M), methanol (up to 100 mu M) and methane. The results shed light on both the geochemical origin of microbial metabolism and the nature of abiotic formate and methane synthesis in modern hydrothermal vents.Three iron minerals found in alkaline hydrothermal vents are shown to convert CO2 and H-2 into formate, acetate and pyruvate in water, suggesting that such reactions could have paved the way for early metabolism.