Foundation for Applied Molecular Evolution and Firebird Biomolecular Sciences LLC, Alachua, Florida, USA.
Astrobiology. 2021 Mar;21(3):298-306. doi: 10.1089/ast.2020.2264. Epub 2021 Feb 2.
While nucleoside 5'-triphosphates are precursors for RNA in modern biology, the presumed difficulty of making these triphosphates on Hadean Earth has caused many prebiotic researchers to consider other activated species for the prebiotic synthesis of RNA. We report here that nickel(II), in the presence of borate, gives substantial amounts (2-3%) of nucleoside 5'-triphosphates upon evaporative heating in the presence of urea, salts, and cyclic trimetaphosphate (CTMP). Also recovered are nucleoside 5'-diphosphates and nucleoside 5'-monophosphates, both likely arising from 5'-triphosphate intermediates. The total level of 5'-phosphorylation is typically 30%. Borate enhances the regiospecificity of phosphorylation, with increased amounts of other phosphorylated species seen in its absence. Experimentally supported paths are already available to make nucleosides in environments likely to have been present on Hadean Earth soon after a midsized 10 to 10 kg impactor, which would also have delivered nickel to the Hadean surface. Further, sources of prebiotic CTMP continue to be proposed. Thus, these results fill in one of the few remaining steps needed to demystify the prebiotic synthesis of RNA and support a continuous model from atmospheric components to oligomeric RNA that is lacking only a mechanism to obtain homochirality in the product RNA.
虽然核苷 5'-三磷酸是现代生物学中 RNA 的前体，但在 Hadean 地球上制造这些三磷酸的假定难度使得许多前生物学家考虑使用其他激活物种来进行 RNA 的前生物合成。我们在此报告，镍（II）在硼酸的存在下，在蒸发加热的同时存在尿素、盐和环三磷酸（CTMP）时，会产生大量（2-3%）的核苷 5'-三磷酸。还回收了核苷 5'-二磷酸和核苷 5'-单磷酸，两者都可能来自 5'-三磷酸中间体。5'-磷酸化的总水平通常为 30%。硼酸增强了磷酸化的区域特异性，在其不存在的情况下会看到其他磷酸化物质的数量增加。在可能已经存在于 Hadean 地球的环境中，在中号 10 到 10 公斤撞击器之后不久，就已经有了制造核苷的实验支持路径，这也将镍输送到 Hadean 表面。此外，还在不断提出前生物 CTMP 的来源。因此，这些结果填补了 RNA 前生物合成中仍然需要解决的少数步骤之一，并支持了从大气成分到寡核苷酸 RNA 的连续模型，该模型仅缺少获得产物 RNA 中手性的机制。
