Nucleobases Undergo Dynamic Rearrangements during RNA Tertiary Folding

JOURNAL OF MOLECULAR BIOLOGY

卷:428

Article

Welty, Robb¹  Hall, Kathleen B.¹ 

[1] Washington Univ, Dept Biochem & Mol Biophys, Sch Med, St Louis, MO 63110 USA

关键词: GTPase center RNA;    2-aminopurine fluorescence;    RNA folding kinetics;    stopped-flow fluorescence;   

DOI  :  10.1016/j.jmb.2016.09.015

来源: Elsevier

【 摘 要 】

The tertiary structure of the GTPase center (GAC) of 23S ribosomal RNA (rRNA) as seen in cocrystals is extremely compact. It is stabilized by long-range hydrogen bonds and nucleobase stacking and by a triloop that forms within its three-way junction. Its folding pathway from secondary structure to tertiary structure has not been previously observed, but it was shown to require Mg2+ ions in equilibrium experiments. The fluorescent nucleotide 2-aminopurine was substituted at selected sites within the 60-nt GAC. Fluorescence intensity changes upon addition of MgCl2 were monitored over a time-course from 1 ms to 100 s as the RNA folds. The folding pathway is revealed here to be hierarchical through several intermediates. Observation of the nucleobases during folding provides a new perspective on the process and the pathway, revealing the dynamics of nucleobase conformational exchange during the folding transitions. (C) 2016 Elsevier Ltd. All rights reserved.

【 授权许可】

Free