Structure of HIV-1 TAR RNA in the absence of ligands reveals a novel conformation of the trinucleotide bulge.Aboul-ela, F., Karn, J., Varani, G.
(1996) Nucleic Acids Res. 24: 3974-3981
- PubMed: 8918800
- PubMed Abstract:
- The Structure of the Human Immunodeficiency Virus Type-1 Tar RNA Reveals Principles of RNA Recognition by Tat Protein
Aboul-Ela, F.,Karn, J.,Varani, G.
(1995) J.Mol.Biol. 253: 313
- Conformation of the Tar RNA-Arginine Complex by NMR Spectroscopy
Puglisi, J.D.,Tan, R.,Calnan, B.J.,Frankel, A.D.,Williamson, J.R.
(1992) Science 257: 76
- High Affinity Binding of Tar RNA by the Human Immunodeficiency Virus Type-1 Tat Protein Requires Base-Pairs in the RNA Stem and Amino Acid Residues Flanking the Basic Region
Churcher, M.J.,Lamont, C.,Hamy, F.,Dingwall, C.,Green, S.M.,Lowe, A.D.,Butler, J.G.,Gait, M.J.,Karn, J.
(1993) J.Mol.Biol. 230: 90
Efficient transcription from the human immunodeficiency virus (HIV) promoter depends on binding of the viral regulatory protein Tat to a cis-acting RNA regulatory element, TAR. Tat binds at a trinucleotide bulge located near the apex of the TAR stem- ...
Efficient transcription from the human immunodeficiency virus (HIV) promoter depends on binding of the viral regulatory protein Tat to a cis-acting RNA regulatory element, TAR. Tat binds at a trinucleotide bulge located near the apex of the TAR stem-loop structure. An essential feature of Tat-TAR interaction is that the protein induces a conformational change in TAR that repositions the functional groups on the bases and the phosphate backbone that are critical for specific intermolecular recognition of TAR RNA. We have previously determined a high resolution structure for the bound form of TAR RNA using heteronuclear NMR. Here, we describe a high resolution structure of the free TAR RNA based on 871 experimentally determined restraints. In the free TAR RNA, bulged residues U23 and C24 are stacked within the helix, while U25 is looped out. This creates a major distortion of the phosphate backbone between C24 and G26. In contrast, in the bound TAR RNA, each of the three residues from the bulge are looped out of the helix and U23 is drawn into proximity with G26 through contacts with an arginine residue that is inserted between the two bases. Thus, TAR RNA undergoes a transition from a structure with an open and accessible major groove to a much more tightly packed structure that is folded around basic side chains emanating from the Tat protein.
MRC Laboratory of Molecular Biology, Cambridge, UK.