2b7c
Yeast guanine nucleotide exchange factor eEF1Balpha K205A mutant in complex with eEF1AYeast guanine nucleotide exchange factor eEF1Balpha K205A mutant in complex with eEF1A
Structural highlights
Function[EF1B_YEAST] Catalytic subunit of the guanine nucleotide exchange factor (GEF) (eEF1B subcomplex) of the eukaryotic elongation factor 1 complex (eEF1). Stimulates the exchange of GDP for GTP on elongation factor 1A (eEF1A), probably by displacing GDP from the nucleotide binding pocket in eEF1A. The 30-fold higher concentration of GTP compared to GDP in cells favors the formation of eEF1A-GTP, which rapidly forms a ternary complex with aminoacyl-tRNA that in turn displaces eEF1B from the complex.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedTo 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. 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[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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