What RNA World? Why a Peptide/RNA Partnership Merits Renewed Experimental Attention.
What RNA World? Why a Peptide/RNA Partnership Merits Renewed Experimental Attention.
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DOI：
10.3390/life5010294
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发表时间：
2015-01-23
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影响因子：
--
通讯作者：
Carter CW
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文献类型：
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作者：
Carter CW
我们回顾了一些观点，认为生物学是从一种互惠的伙伴关系中产生的，在这种伙伴关系中，小的祖先寡肽和寡核苷酸最初都贡献了基本的信息编码和催化速率加速，并且RNA的优越信息承载质量和蛋白质的优越催化潜力仅随着遗传密码的逐渐发明而从这些复合物中出现。在证明具有催化作用的RNA之前的近十年，这一设想的一个连贯的结构基础就已经被阐明了。来自两种合成酶类的高度保守序列的平行分层催化谱现在增加了它们作为单个基因相反链的翻译产物产生的可能性。义/反义编码提供了一种新的生物信息学度量，可以用于远比从单个超家族的多个序列比对重建的系统发育关系。tRNA受体和反密码子编码特性不同的证据，以及实验证明两个合成酶家族ATP结合位点确实可以由同一基因的相反链编码的证据，补充了这些生化和生物信息学数据，为从简单的、立体化学编码的、相互催化的肽/RNA复合物，通过最早的肽催化剂到当代氨基酰-tRNA合成酶的关键中间体建立了坚实的基础。这种情况记录了增加复杂性的途径，从而消除了对单个聚合物既具有催化作用又具有信息分子的需求。
We review arguments that biology emerged from a reciprocal partnership in which small ancestral oligopeptides and oligonucleotides initially both contributed rudimentary information coding and catalytic rate accelerations, and that the superior information-bearing qualities of RNA and the superior catalytic potential of proteins emerged from such complexes only with the gradual invention of the genetic code. A coherent structural basis for that scenario was articulated nearly a decade before the demonstration of catalytic RNA. Parallel hierarchical catalytic repertoires for increasingly highly conserved sequences from the two synthetase classes now increase the likelihood that they arose as translation products from opposite strands of a single gene. Sense/antisense coding affords a new bioinformatic metric for phylogenetic relationships much more distant than can be reconstructed from multiple sequence alignments of a single superfamily. Evidence for distinct coding properties in tRNA acceptor stems and anticodons, and experimental demonstration that the two synthetase family ATP binding sites can indeed be coded by opposite strands of the same gene supplement these biochemical and bioinformatic data, establishing a solid basis for key intermediates on a path from simple, stereochemically coded, reciprocally catalytic peptide/RNA complexes through the earliest peptide catalysts to contemporary aminoacyl-tRNA synthetases. That scenario documents a path to increasing complexity that obviates the need for a single polymer to act both catalytically and as an informational molecule.