Centro de Astrobiología (CAB) CSIC-INTA, Dpto. Evolución Molecular, Carretera de Ajalvir, km 4, Torrejón de Ardoz, 28850, Madrid, Spain.
Sci Rep. 2022 Sep 7;12(1):15140. doi: 10.1038/s41598-022-19474-0.
Herein, the potential of alkaline hydrothermal environments for the synthesis of possible ancestral pre-RNA nucleobases using cyanide as a primary source of carbon and nitrogen is described. Water cyanide polymerizations were assisted by microwave radiation to obtain high temperature and a relatively high pressure (MWR, 180 °C, 15 bar) and were also carried out using a conventional thermal system (CTS, 80 °C, 1 bar) to simulate subaerial and aerial hydrothermal conditions, respectively, on the early Earth. For these syntheses, the initial concentration of cyanide and the diffusion effects were studied. In addition, it is well known that hydrolysis conditions are directly related to the amount and diversity of organic molecules released from cyanide polymers. Thus, as a first step, we studied the effect of several hydrolysis procedures, generally used in prebiotic chemistry, on some of the potential pre-RNA nucleobases of interest, together with some of their isomers and/or deamination products, also presumably formed in these complex reactions. The results show that the alkaline hydrothermal scenarios with a relatively constant pH are good geological scenarios for the generation of noncanonical nucleobases using cyanide as a prebiotic precursor.
本文描述了利用氰化物作为碳和氮的主要来源，在碱性热液环境中合成可能的原始 RNA 碱基的潜力。水合氰化物的聚合反应在微波辐射的辅助下进行，以获得高温和相对高压（MWR，180°C，15 巴），也使用传统的热系统（CTS，80°C，1 巴）进行，分别模拟早期地球上的陆上和空中热液条件。对于这些合成，研究了氰化物的初始浓度和扩散效应。此外，众所周知，水解条件与从氰化物聚合物中释放的有机分子的数量和多样性直接相关。因此，作为第一步，我们研究了几种通常用于前生物化学的水解程序对一些感兴趣的潜在预 RNA 碱基及其异构体和/或脱氨产物的影响，这些产物也可能在前生物化学中形成复杂的反应。结果表明，碱性热液条件下 pH 相对稳定，是利用氰化物作为前生物前体生成非规范碱基的良好地质条件。
