Hassenkam Tue, Damer Bruce, Mednick Gabriel, Deamer David
Globe Institute, University of Copenhagen, DK-1350 Copenhagen, Denmark.
Department of Biomolecular Engineering, University of California, Santa Cruz, CA 95064, USA.
Life (Basel). 2020 Nov 30;10(12):321. doi: 10.3390/life10120321.
It is possible that early life relied on RNA polymers that served as ribozyme-like catalysts and for storing genetic information. The source of such polymers is uncertain, but previous investigations reported that wet-dry cycles simulating prebiotic hot springs provide sufficient energy to drive condensation reactions of mononucleotides to form oligomers. The aim of the study reported here was to visualize the products by atomic force microscopy. In addition to globular oligomers, ring-like structures ranging from 10-200 nm in diameter, with an average around 30-40 nm, were abundant, particularly when nucleotides capable of base pairing were present. The thickness of the rings was consistent with single stranded products, but some had thicknesses indicating base pair stacking. Others had more complex structures in the form of short polymer attachments and pairing of rings. These observations suggest the possibility that base-pairing may promote polymerization during wet-dry cycling followed by solvation of the rings. We conclude that RNA-like rings and structures could have been synthesized non-enzymatically on the prebiotic Earth, with sizes sufficient to fold into ribozymes and genetic molecules required for life to begin.
早期生命可能依赖于作为类核酶催化剂并用于存储遗传信息的RNA聚合物。此类聚合物的来源尚不确定，但先前的研究报告称，模拟益生元温泉的干湿循环提供了足够的能量来驱动单核苷酸的缩合反应以形成寡聚物。本文所报告研究的目的是通过原子力显微镜观察产物。除了球状寡聚物外，还大量存在直径为10 - 200纳米、平均约为30 - 40纳米的环状结构，尤其是当存在能够碱基配对的核苷酸时。这些环的厚度与单链产物一致，但有些环的厚度表明存在碱基对堆积。其他环具有更复杂的结构，形式为短聚合物附着物和环的配对。这些观察结果表明，在干湿循环过程中碱基配对可能促进聚合作用，随后环发生溶剂化。我们得出结论，类似RNA的环和结构可能在生命起源前的地球上非酶促合成，其大小足以折叠成生命起源所需的核酶和遗传分子。
