PDF(Pubmed)
Abstract：
To track down the possible roots of life, various models for the initial living system composed of different combinations of the three extant biopolymers, RNA, DNA, and proteins, are presented. The suitability of each molecular set is assessed according to its ability to emerge autonomously, sustain, and evolve continuously towards life as we know it. The analysis incorporates current biological knowledge gained from high-resolution structural data and large sequence datasets, together with experimental results concerned with RNA replication and with the activity demonstrated by standalone constructs of the ribosomal Peptidyl Transferase Center region. The scrutiny excludes the DNA-protein combination and assigns negligible likelihood to the existence of an RNA-DNA world, as well as to an RNA world that contained a replicase made of RNA. It points to the precedence of an RNA-protein system, whose model of emergence suggests specific processes whereby a coded proto-ribosome ribozyme, specifically aminoacylated proto-tRNAs and a proto-polymerase enzyme, could have autonomously emerged, cross-catalyzing the formation of each other. This molecular set constitutes a feasible starting point for a continuous evolutionary path, proceeding via natural processes from the inanimate matter towards life as we know it.
摘要：
为了追踪生命的可能根源，由三种现存生物聚合物的不同组合组成的初始生命系统的各种模型，RNA,DNA,和蛋白质，被呈现。每个分子组的适用性根据其自主出现的能力进行评估，维持,并不断向我们所知的生命进化。该分析结合了从高分辨率结构数据和大型序列数据集获得的当前生物学知识，以及与RNA复制和核糖体肽基转移酶中心区域的独立构建体证明的活性有关的实验结果。审查排除了DNA-蛋白质的组合，并赋予RNA-DNA世界的存在可以忽略不计的可能性，以及包含由RNA制成的复制酶的RNA世界。它指出了RNA-蛋白质系统的优先地位，其出现模型提示了特定的过程，从而产生了编码的原核糖体核酶，特别是氨基酰化的原tRNA和原聚合酶，可以自主出现，交叉催化彼此的形成。该分子集构成了连续进化路径的可行起点，通过从无生命物质到我们所知的生命的自然过程。
