High-energy chemistry of formamide: A unified mechanism of nucleobase formation
High-energy chemistry of formamide: A unified mechanism of nucleobase formation
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DOI：
10.1073/pnas.1412072111
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发表时间：
2015-01-20
影响因子：
11.1
通讯作者：
Civis, Svatopluk
中科院分区：
文献类型：
--
作者：
Ferus, Martin;Nesvorny, David;Civis, Svatopluk
晚期重轰炸（LHB）时期和大约40亿年前地球生命的出现的巧合表明，外星撞击可能有助于合成第一批生命分子的组成部分。我们模拟了在外星物体撞击期间甲酰胺的核碱基的高能合成。一个高功率的激光已被用来诱导的等离子体的冲击产生的介质击穿。结果表明，甲酰胺分子的初始解离可产生大量高活性CN和NH自由基，其可进一步与甲酰胺反应以产生腺嘌呤、鸟嘌呤、胞嘧啶和尿嘧啶。基于GC-MS，高分辨率FTIR光谱结果，以及理论计算，我们提出了一个全面的机理模型，该模型考虑了所研究的撞击化学中发生的所有步骤。因此，我们的研究结果表明，在LHB期间比之前和之后多一个数量级的外星撞击不仅可以摧毁现有的古代生命形式，而且还可以有助于创造生物分子。
The coincidence of the Late Heavy Bombardment (LHB) period and the emergence of terrestrial life about 4 billion years ago suggest that extraterrestrial impacts could contribute to the synthesis of the building blocks of the first life-giving molecules. We simulated the high-energy synthesis of nucleobases from formamide during the impact of an extraterrestrial body. A high-power laser has been used to induce the dielectric breakdown of the plasma produced by the impact. The results demonstrate that the initial dissociation of the formamide molecule could produce a large amount of highly reactive CN and NH radicals, which could further react with formamide to produce adenine, guanine, cytosine, and uracil. Based on GC-MS, high-resolution FTIR spectroscopic results, as well as theoretical calculations, we present a comprehensive mechanistic model, which accounts for all steps taking place in the studied impact chemistry. Our findings thus demonstrate that extraterrestrial impacts, which were one order of magnitude more abundant during the LHB period than before and after, could not only destroy the existing ancient life forms, but could also contribute to the creation of biogenic molecules.