Formation of Methylamine and Ethylamine in Extraterrestrial Ices and Their Role as Fundamental Building Blocks of Proteinogenic α-amino Acids
Formation of Methylamine and Ethylamine in Extraterrestrial Ices and Their Role as Fundamental Building Blocks of Proteinogenic α-amino Acids
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DOI：
10.3847/1538-4357/aa7edd
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发表时间：
2017-08-10
影响因子：
4.9
通讯作者：
Kaiser, Ralf I.
中科院分区：
文献类型：
--
作者：
Foerstel, Marko;Bergantini, Alexandre;Kaiser, Ralf I.
- CH-NH 2部分代表所有蛋白质氨基酸的基本构建单元，其中环状氨基酸脯氨酸是特例（脯氨酸中的-CH-NH-）。利用化学逆合成，我们发现，甲胺（CH 3 NH 2）和/或乙胺（CH 3CH 2NH 2）是必不可少的前体在形成每个蛋白质氨基酸。在本研究中，我们阐明了非生物形成的甲胺和乙胺氨（NH3）和甲烷（CH 4）冰暴露于高能宇宙辐射在彗星和星际模型冰产生的二次电子。我们的实验表明，甲胺和乙胺是关键的反应产物在辐照冰组成的氨和甲烷。使用同位素取代的研究，我们进一步获得有价值的信息对甲胺的具体反应途径。最近在67 P/Churyumov-Gerasimenko的昏迷中鉴定出甲胺和乙胺以及甘氨酸，强调了它们在外星形成氨基酸的潜力。
The -CH-NH2 moiety represents the fundamental building block of all proteinogenic amino acids, with the cyclic amino acid proline being a special case (-CH-NH-in proline). Exploiting a chemical retrosynthesis, we reveal that methylamine (CH3NH2) and/or ethylamine (CH3CH2NH2) are essential precursors in the formation of each proteinogenic amino acid. In the present study we elucidate the abiotic formation of methylamine and ethylamine from ammonia (NH3) and methane (CH4) ices exposed to secondary electrons generated by energetic cosmic radiation in cometary and interstellar model ices. Our experiments show that methylamine and ethylamine are crucial reaction products in irradiated ices composed of ammonia and methane. Using isotopic substitution studies we further obtain valuable information on the specific reaction pathways toward methylamine. The very recent identification of methylamine and ethylamine together with glycine in the coma of 67P/Churyumov-Gerasimenko underlines their potential to the extraterrestrial formation of amino acids.