1nu4
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(New page: 200px<br /> <applet load="1nu4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1nu4, resolution 1.80Å" /> '''U1A RNA binding dom...)
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Revision as of 16:18, 12 November 2007
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U1A RNA binding domain at 1.8 angstrom resolution reveals a pre-organized C-terminal helix
Overview
The human U1A RNA-binding domain (RBD1) adopts one of the most common, protein folds, the RNA-recognition motif, and is a paradigm for, understanding RNA-protein interactions. A 2.8 A resolution structure of, the unbound RBD1 has previously been determined [Nagai et al. (1990)., Nature (London), 348, 515-520] and revealed a well defined alpha/beta core, with disordered termini. Using a longer construct, a 1.8 A resolution, structure of the unbound domain was determined that reveals an ordered, C-terminal helix. The presence of this helix is consistent with a solution, structure of the free domain [Avis et al. (1996). J. Mol. Biol. 257, 398-411]; however, in the solution structure the helix occludes the, RNA-binding surface. In the present structure, the helix occupies a, position similar to that seen in a 1.9 A resolution RNA-RBD1 complex, structure [Oubridge et al. (1994). Nature (London), 372, 432-438]. The, crystals in this study were grown from 2.2 M sodium malonate. It is, possible that the high salt concentration helps to orient the C-terminal, helix in the RNA-bound conformation by strengthening hydrophobic, interactions between the buried face of the helix and the alpha/beta core, of the protein. Alternatively, the malonate (several molecules of which, are bound in the vicinity of the RNA-binding surface) may mimic RNA.
About this Structure
1NU4 is a Single protein structure of sequence from Homo sapiens with MG and MLA as ligands. Full crystallographic information is available from OCA.
Reference
U1A RNA-binding domain at 1.8 A resolution., Rupert PB, Xiao H, Ferre-D'Amare AR, Acta Crystallogr D Biol Crystallogr. 2003 Aug;59(Pt 8):1521-4. Epub 2003, Jul 23. PMID:12876372
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