The role of sugar-backbone heterogeneity and chimeras in the simultaneous emergence of RNA and DNA
The role of sugar-backbone heterogeneity and chimeras in the simultaneous emergence of RNA and DNA
复制标题
DOI：
10.1038/s41557-019-0322-x
复制
发表时间：
2019-11-01
期刊：
影响因子：
21.8
通讯作者：
Krishnamurthy, Ramanarayanan
中科院分区：
文献类型：
--
作者：
Bhowmik, Subhendu;Krishnamurthy, Ramanarayanan
关于RNA和DNA起源的假说通常集中在原始系统(Pre-RNA或RNA)的益生合成上，这导致了它的后代。然而，在合成遗传聚合物方面缺乏特异性可能会导致嵌合序列；这种序列的作用和命运尚不清楚。在这里，我们表明嵌合体，以混合苏糖核酸(TNA)-RNA和RNA-DNA寡核苷酸为例，优先与均一的TNA、RNA和DNA配体结合并作为模板。嵌合模板可以作为催化剂，介导低聚物的连接以得到均一的主干序列，并且嵌合模板的再生增强了可能的交叉催化循环与放大的情景。这一过程提供了异质到同质情景的原则证明，也证明了DNA可能与RNA同时出现，而不是它后来的后代。
Hypotheses of the origins of RNA and DNA are generally centred on the prebiotic synthesis of a pristine system (pre-RNA or RNA), which gives rise to its descendent. However, a lack of specificity in the synthesis of genetic polymers would probably result in chimeric sequences; the roles and fate of such sequences are unknown. Here, we show that chimeras, exemplified by mixed threose nucleic acid (TNA)-RNA and RNA-DNA oligonucleotides, preferentially bind to, and act as templates for, homogeneous TNA, RNA and DNA ligands. The chimeric templates can act as a catalyst that mediates the ligation of oligomers to give homogeneous backbone sequences, and the regeneration of the chimeric templates potentiates a scenario for a possible cross-catalytic cycle with amplification. This process provides a proof-of-principle demonstration of a heterogeneity-to-homogeneity scenario and also gives credence to the idea that DNA could appear concurrently with RNA, instead of being its later descendent.