Remnants of an Ancient Metabolism without Phosphate
Remnants of an Ancient Metabolism without Phosphate
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DOI：
10.1016/j.cell.2017.02.001
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发表时间：
2017-03-09
期刊：
影响因子：
64.5
通讯作者：
Segre, Daniel
中科院分区：
文献类型：
--
作者：
Goldford, Joshua E.;Hartman, Hyman;Segre, Daniel
磷酸盐对所有生命系统都是必不可少的，是遗传和代谢机制的基石。然而，目前还不清楚磷酸盐如何在原始地球上发挥这些核心作用，因为它的地球化学可及性很差。我们使用系统生物学方法来探索替代假设，即蛋白质代谢可能在磷酸盐掺入之前出现。令人惊讶的是，weidentified一个神秘的磷酸盐独立的核心代谢产生的简单的益生元化合物。该网络被预测为支持广泛类别的关键生物分子的生物合成。它的富集利用铁硫簇的酶，以及热力学瓶颈更容易克服硫酯而不是磷酸盐耦合的事实，表明这个网络可能构成早期无磷酸盐非酶生物化学的“代谢化石”。我们的研究结果证实并扩展了以前的建议，一个假定的硫酯为基础的代谢可能早于磷酸盐和RNA为基础的遗传系统的掺入。
Phosphate is essential for all living systems, serving as a building block of genetic and metabolic machinery. However, it is unclear how phosphate could have assumed these central roles on primordial Earth, given its poor geochemical accessibility. We used systems biology approaches to explore the alternative hypothesis that a protometabolism could have emerged prior to the incorporation of phosphate. Surprisingly, weidentified a cryptic phosphate-independent core metabolism producible from simple prebiotic compounds. This network is predicted to support the biosynthesis of a broad category of key biomolecules. Its enrichment for enzymes utilizing iron-sulfur clusters, and the fact that thermodynamic bottlenecks are more readily overcome by thioester rather than phosphate couplings, suggest that this network may constitute a "metabolic fossil'' of an early phosphate-free nonenzymatic biochemistry. Our results corroborate and expand previous proposals that a putative thioester-based metabolism could have predated the incorporation of phosphate and an RNA-based genetic system.