Roovers Martine, Droogmans Louis, Grosjean Henri
Labiris, Avenue E. Gryson 1, 1070 Bruxelles, Belgium.
Laboratoire de Chimie Biologique, Université Libre de Bruxelles (ULB), Labiris, Avenue E. Gryson 1, 1070 Bruxelles, Belgium.
Genes (Basel). 2021 Jan 22;12(2):140. doi: 10.3390/genes12020140.
The high conservation of nucleotides of the T-loop, including their chemical identity, are hallmarks of tRNAs from organisms belonging to the three Domains of Life. These structural characteristics allow the T-loop to adopt a peculiar intraloop conformation able to interact specifically with other conserved residues of the D-loop, which ultimately folds the mature tRNA in a unique functional canonical L-shaped architecture. Paradoxically, despite the high conservation of modified nucleotides in the T-loop, enzymes catalyzing their formation depend mostly on the considered organism, attesting for an independent but convergent evolution of the post-transcriptional modification processes. The driving force behind this is the preservation of a native conformation of the tRNA elbow that underlies the various interactions of tRNA molecules with different cellular components.
T环核苷酸的高度保守性，包括其化学特性，是来自生命三域中各生物体的tRNA的标志。这些结构特征使T环能够采用一种特殊的环内构象，能够与D环的其他保守残基特异性相互作用，最终将成熟tRNA折叠成独特的功能性标准L形结构。矛盾的是，尽管T环中修饰核苷酸高度保守，但催化其形成的酶大多取决于所考虑的生物体，这证明了转录后修饰过程的独立但趋同的进化。其背后的驱动力是tRNA肘部天然构象的保留，这是tRNA分子与不同细胞成分各种相互作用的基础。
