Relicts and models of the RNA world
Relicts and models of the RNA world
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DOI：
10.1017/s1473550405002521
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发表时间：
2005-01-01
影响因子：
1.7
通讯作者：
Karetnikov, Alexey
中科院分区：
文献类型：
--
作者：
Lehto, Kirsi;Karetnikov, Alexey
人们普遍认为，目前以dna -RNA-蛋白质为基础的生命形式是从以前的RNA-蛋白质为基础的生命形式进化而来的，而这些生命形式又仅仅是从RNA复制子进化而来的。根据基本原理，可以假设早期的RNA复制子在从环境中获得所有构建块方面是完全异养的。在没有蛋白质催化剂的情况下，它们的基本生命功能必须由简单的功能结构和机制介导，如RNA二级结构、RNA-RNA相互作用和RNA介导的催化作用，也可能由催化矿物或粘土介导。RNA催化剂在早期生命形式中的核心作用得到了一些催化RNA在当前生命形式中仍然发挥核心生物学功能的事实的支持，至少其中一些可能是早期RNA生命的分子残留物。RNA催化的代谢反应和分子化石在真核生物中比在原核生物中更为保守，这表明线性真核生物基因组可能比圆形原核生物基因组更接近于早期RNA复制子的结构和功能。今天的RNA病毒和类病毒最终使用简单的生命策略，这可能与早期RNA复制子使用的策略相似。因此，病毒和类病毒的分子和功能特性可被视为结构和复制机制的例子或模型，这些结构和复制机制可能已用于早期生物聚合物的复制。2005年2月2日收，2005年4月20日收
It is widely believed that the current DNA-RNA-protein-based life forms have evolved from preceding RNA-protein-based life forms, and these again, from mere RNA replicons. By rationale, it can be assumed that the early RNA replicons were fully heterotrophic in terms of obtaining all their building blocks from their environment. In the absence of protein catalysts, their essential life functions had to be mediated by simple functional structures and mechanisms, such as RNA secondary structures, RNA-RNA interactions and RNA-mediated catalysis, and possibly by catalytic minerals or clays. The central role of RNA catalysts in early life forms is supported by the fact that several catalytic RNAs still perform central biological functions in current life forms, and at least some of these may be derived as molecular relicts from the early RNA-based life. The RNA-catalysed metabolic reactions and molecular fossils are more conserved in the eukaryotic life forms than in the prokaryotes, suggesting that the linear eukaryote genomes may more closely resemble the structure and function of the early RNA replicons, than what do the circular prokaryote genomes. Present-day RNA viruses and viroids utilize ultimately simple life strategies, which may be similar to those used by the early RNA replicons. Thus, molecular and functional properties of viruses and viroids may be considered as examples or models of the structures and replication mechanisms, which might have been used for the replication of the early biopolymers. Received 2 February 2005, accepted 20 April 2005