Heterogeneous structures formed by conserved RNA sequences within the HIV reverse transcription initiation site
- 1Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305-5126, USA
- 2Biophysics Program, Stanford University School of Medicine, Stanford, California 94305-5126, USA
- Corresponding author: epuglisi{at}stanford.edu
Abstract
Reverse transcription is a key process in the early steps of HIV infection. This process initiates within a specific complex formed by the 5′ UTR of the HIV genomic RNA (vRNA) and a host primer tRNALys3. Using nuclear magnetic resonance (NMR) spectroscopy and single-molecule fluorescence spectroscopy, we detect two distinct conformers adopted by the tRNA/vRNA initiation complex. We directly show that an interaction between the conserved 8-nucleotide viral RNA primer activation signal (PAS) and the primer tRNA occurs in one of these conformers. This intermolecular PAS interaction likely induces strain on a vRNA intramolecular helix, which must be broken for reverse transcription to initiate. We propose a mechanism by which this vRNA/tRNA conformer relieves the kinetic block formed by the vRNA intramolecular helix to initiate reverse transcription.
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Footnotes
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Article published online ahead of print. Article and publication date are at http://www.rnajournal.org/cgi/doi/10.1261/rna.056804.116.
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Freely available online through the RNA Open Access option.
- Received April 5, 2016.
- Accepted August 3, 2016.
This article, published in RNA, is available under a Creative Commons License (Attribution 4.0 International), as described at http://creativecommons.org/licenses/by/4.0/.