2b7c
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(New page: 200px<br /><applet load="2b7c" size="450" color="white" frame="true" align="right" spinBox="true" caption="2b7c, resolution 1.8Å" /> '''Yeast guanine nucleot...)
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Revision as of 06:29, 21 November 2007
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Yeast guanine nucleotide exchange factor eEF1Balpha K205A mutant in complex with eEF1A
Overview
To sustain efficient translation, eukaryotic elongation factor B alpha, (eEF1B alpha) functions as the guanine nucleotide exchange factor for, eEF1A. Stopped-flow kinetics using 2'-(or 3')-O-N-methylanthraniloyl, (mant)-GDP showed spontaneous release of nucleotide from eEF1A is, extremely slow and accelerated 700-fold by eEF1B alpha. The eEF1B, alpha-stimulated reaction was inhibited by Mg2+ with a K(1/2) of 3.8 mM., Previous structural studies predicted the Lys-205 residue of eEF1B alpha, plays an important role in promoting nucleotide exchange by disrupting the, Mg2+ binding site. Co-crystal structures of the lethal K205A mutant in the, catalytic C terminus of eEF1B alpha with eEF1A and eEF1A.GDP established, that the lethality was not due to a structural defect. Instead, the K205A, mutant drastically reduced the nucleotide exchange activity even at very, low concentrations of Mg2+. A K205R eEF1B alpha mutant on the other hand, was functional in vivo and showed nearly wild-type nucleotide dissociation, rates but almost no sensitivity to Mg2+. These results indicate the, significant role of Mg2+ in the nucleotide exchange reaction by eEF1B, alpha and establish the catalytic function of Lys-205 in displacing Mg2+, from its binding site.
About this Structure
2B7C is a Protein complex structure of sequences from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
Reference
Mg2+ and a key lysine modulate exchange activity of eukaryotic translation elongation factor 1B alpha., Pittman YR, Valente L, Jeppesen MG, Andersen GR, Patel S, Kinzy TG, J Biol Chem. 2006 Jul 14;281(28):19457-68. Epub 2006 May 4. PMID:16675455
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