固碳
化学
乙酰辅酶A
古细菌
自养
生物化学
酶
生物合成
立体化学
代谢途径
生物
光合作用
基因
古生物学
细菌
作者
Sreejith Jayasree Varma,Kamila B. Muchowska,Paul Chatelain,Joseph Moran
标识
DOI:10.1038/s41559-018-0542-2
摘要
Autotrophic theories for the origin of life propose that CO2 was the carbon source for primordial biosynthesis. Among the six known CO2 fixation pathways in nature, the acetyl-CoA (AcCoA; or Wood–Ljungdahl) pathway is the most ancient, and relies on transition metals for catalysis. Modern microbes that use the AcCoA pathway typically fix CO2 with electrons from H2, which requires complex flavin-based electron bifurcation. This presents a paradox: how could primitive metabolic systems have fixed CO2 before the origin of proteins? Here, we show that native transition metals (Fe0, Ni0 and Co0) selectively reduce CO2 to acetate and pyruvate—the intermediates and end-products of the AcCoA pathway—in near millimolar concentrations in water over hours to days using 1–40 bar CO2 and at temperatures from 30 to 100 °C. Geochemical CO2 fixation from native metals could have supplied critical C2 and C3 metabolites before the emergence of enzymes. The acetyl-CoA pathway is the most ancient CO2 fixation pathway in nature. Here, the authors show that metals selectively reduce CO2 to the intermediates and end-products of the acetyl-CoA pathway, which is consistent with a prebiotic origin of this pathway.
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