Krupp G
Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität, Kiel, Germany.
Mol Biol Rep. 1995;22(2-3):177-80. doi: 10.1007/BF00988725.
TransferRNA recognition was used as leit-motiv in the illustration of possible links between a hypothetical primordial RNA world and the contemporary DNA world. In an RNA world, 'proto-tRNA' could have functioned as replication origin and as primitive telomere. Possibly, this primitive structure is preserved in a 'universal substrate' for modern tRNA-specific enzymes. The combination of acceptor stem and T arm (plus a linker) was finally revealed as sufficient for the recognition by prokaryotic and eukaryotic RNase P, as well as other tRNA enzymes. In modern life forms, a tRNA-like element in viral RNAs still serves as replication origin, and furthermore, the recognition of similar structures as cryptic promoters is universally conserved for template-dependent RNA polymerases. Another common property of modern polymerases is their high, but clearly limited and condition-dependent substrate specificity. Very likely, also substrate recognition by primitive polymerases was not more stringent, and this lead to the occurrence of mixed nucleic acids as intermediates in the transition of genomic RNA to contemporary genomic DNA.
在阐述假设的原始RNA世界与当代DNA世界之间可能存在的联系时，tRNA识别被用作主线。在RNA世界中，“原始tRNA”可能曾作为复制起点和原始端粒发挥作用。这种原始结构可能保存在现代tRNA特异性酶的“通用底物”中。最终发现，受体茎和T臂（加上一个连接体）的组合足以被原核和真核RNase P以及其他tRNA酶识别。在现代生命形式中，病毒RNA中的类tRNA元件仍作为复制起点，此外，模板依赖性RNA聚合酶对类似结构作为隐蔽启动子的识别是普遍保守的。现代聚合酶的另一个共同特性是它们具有很高但明显有限且依赖条件的底物特异性。很可能，原始聚合酶对底物的识别也没有更严格，这导致了混合核酸作为基因组RNA向当代基因组DNA转变过程中的中间体出现。
