RNA versatility governs tRNA function

• Published in: BioEssays Vol. 38; no. 5; pp. 465 - 473
• Main Author: Kuhn, Claus-D.
• Format: Journal Article
• Language: English
• Published: Cambridge Blackwell Publishing Ltd 01.05.2016; Wiley Subscription Services, Inc
• Subjects: CCA-adding enzyme; Flexibility; RNA folding; structural biology; translation; tRNA
• ISSN: 0265-9247; 1521-1878
• DOI: 10.1002/bies.201500190

tRNAs undergo multiple conformational changes during the translation cycle that are required for tRNA translocation and proper communication between the ribosome and translation factors. Recent structural data on how destabilized tRNAs utilize the CCA‐adding enzyme to proofread themselves put a spotlight on tRNA flexibility beyond the translation cycle. In analogy to tRNA surveillance, this review finds that other processes also exploit versatile tRNA folding to achieve, amongst others, specific aminoacylation, translational regulation by riboswitches or a block of bacterial translation. tRNA flexibility is thereby not restricted to the hinges utilized during translation. In contrast, the flexibility of tRNA is distributed all over its L‐shape and is actively exploited by the tRNA‐interacting partners to discriminate one tRNA from another. Since the majority of tRNA modifications also modulate tRNA flexibility it seems that cells devote enormous resources to tightly sense and regulate tRNA structure. This is likely required for error‐free protein synthesis. Recent structural insights into tRNA surveillance by the CCA‐adding enzyme, tRNA aminoacylation, and T‐box regulated translation accentuate that the conformational flexibility of tRNA is not restricted to the translation cycle on the ribosome. Rather, it is a general prerequisite for tRNA function in vivo.