Exploring TAR-RNA aptamer loop-loop interaction by X-ray crystallography, UV spectroscopy and surface plasmon resonance.Reportar como inadecuado




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* Corresponding author 1 Chimie et Biologie des Membranes et des Nanoobjets 2 Institut Européen de Chimie et Biologie 3 SSOLEIL - Synchrotron SOLEIL 4 ARN : régulations naturelle et artificielle

Abstract : In HIV-1, trans-activation of transcription of the viral genome is regulated by an imperfect hairpin, the trans-activating responsive TAR RNA element, located at the 5- untranslated end of all viral transcripts. TAR acts as a binding site for viral and cellular proteins. In an attempt to identify RNA ligands that would interfere with the virus life-cycle by interacting with TAR, an in vitro selection was previously carried out. RNA hairpins that formed kissing-loop dimers with TAR were selected Ducong?. and Toulm?J 1999 RNA, 5:1605-1614. We describe here the crystal structure of TAR bound to a high-affinity RNA aptamer. The two hairpins form a kissing complex and interact through six Watson-Crick base pairs. The complex adopts an overall conformation with an inter-helix angle of 28.1 degrees , thus contrasting with previously reported solution and modelling studies. Structural analysis reveals that inter-backbone hydrogen bonds between ribose 2- hydroxyl and phosphate oxygens at the stem-loop junctions can be formed. Thermal denaturation and surface plasmon resonance experiments with chemically modified 2-O-methyl incorporated into both hairpins at key positions, clearly demonstrate the involvement of this intermolecular network of hydrogen bonds in complex stability.

Keywords : Kissing complex RNA Surface Plasmon Resonance aptamer HIV-1





Autor: Isabelle Lebars - Pierre Legrand - Ahissan Aimé - Noël Pinaud - Sébastien Fribourg - Carmelo Di Primo -

Fuente: https://hal.archives-ouvertes.fr/



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