1b23
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(New page: 200px<br /><applet load="1b23" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b23, resolution 2.6Å" /> '''E. coli cysteinyl-tRN...)
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Revision as of 09:10, 20 November 2007
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E. coli cysteinyl-tRNA and T. aquaticus elongation factor EF-TU:GTP ternary complex
Overview
BACKGROUND:. The translation elongation factor EF-Tu in its GTP-bound, state forms a ternary complex with any aminoacylated tRNA (aa-tRNA), except initiator tRNA and selenocysteinyl-tRNA. This complex delivers, aa-tRNA to the ribosomal A site during the elongation cycle of, translation. The crystal structure of the yeast Phe-tRNAPhe ternary, complex with Thermus aquaticus EF-Tu-GDPNP (Phe-TC) has previously been, determined as one representative of this general yet highly discriminating, complex formation. RESULTS: The ternary complex of Escherichia coli, Cys-tRNACys and T. aquaticus EF-Tu-GDPNP (Cys-TC) has been solved and, refined at 2.6 degrees resolution. Conserved and variable features of the, aa-tRNA recognition and binding by EF-Tu-GTP have been revealed by, comparison with the Phe-TC structure. New tertiary interactions are, observed in the tRNACys structure. A 'kissing complex' is observed in the, very close crystal packing arrangement. CONCLUSIONS: The recognition of, Cys-tRNACys by EF-Tu-GDPNP is restricted to the aa-tRNA motif previously, identified in Phe-TC and consists of the aminoacylated 3' end, the, phosphorylated 5' end and one side of the acceptor stem and T stem. The, aminoacyl bond is recognized somewhat differently, yet by the same primary, motif in EF-Tu, which suggests that EF-Tu adapts to subtle variations in, this moiety among all aa-tRNAs. New tertiary interactions revealed by the, Cys-tRNACys structure, such as a protonated C16:C59 pyrimidine pair, a, G15:G48 'Levitt pair' and an s4U8:A14:A46 base triple add to the generic, understanding of tRNA structure from sequence. The structure of the, 'kissing complex' shows a quasicontinuous helix with a distinct shape, determined by the number of base pairs.
About this Structure
1B23 is a Single protein structure of sequence from Escherichia coli and Thermus aquaticus with MG, SO4, CYS and GNP as ligands. Full crystallographic information is available from OCA.
Reference
The crystal structure of Cys-tRNACys-EF-Tu-GDPNP reveals general and specific features in the ternary complex and in tRNA., Nissen P, Thirup S, Kjeldgaard M, Nyborg J, Structure. 1999 Feb 15;7(2):143-56. PMID:10368282
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