DOI: 10.1101/498907Dec 18, 2018Paper

Dynamic ensemble of HIV-1 RRE stem IIB reveals non-native conformations that disrupt the Rev binding site

BioRxiv : the Preprint Server for Biology
Chia-Chieh ChuHashim M. Al-Hashimi

Abstract

The HIV-1 Rev response element (RRE) RNA element mediates the nuclear export of intron containing viral RNAs by forming an oligomeric complex with the viral protein Rev. Stem IIB and nearby stem II three-way junction nucleate oligomerization through cooperative binding of two Rev molecules. Conformational flexibility at this RRE region has been shown to be important for Rev binding. However, the nature of the flexibility has remained elusive. Here, using NMR relaxation dispersion, including a new strategy for directly observing transient conformational states in large RNAs, we find that stem IIB alone or when part of the larger RREII three-way junction robustly exists in dynamic equilibrium with non-native excited state (ES) conformations that have a combined population of ~ 20 %. The ESs disrupt the Rev binding site by changing local secondary structure and their stabilization via point substitution mutations decreases the binding affinity to the Rev arginine-rich motif (ARM) by 15 to 80 fold. The ensemble clarifies the conformational flexibility observed in stem IIB, reveals long-range conformational coupling between stem IIB and the three-way junction that may play roles in cooperative Rev binding, and also identifies non-na...Continue Reading

Related Concepts

Introns
Protein Conformation
RNA
RNA, Viral
Stem Cells
Viral Proteins
Protein Structure, Secondary
Relaxation Therapy
EIF5A protein, human
ARMET protein, human

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