Primary Citation of Related Structures: 2B7B, 2B7C
PubMed Abstract:
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 ...
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.
Related Citations:
Structural basis for nucleotide exchange and competition with tRNA in the yeast elongation factor complex eEF1A:eEF1Balpha Andersen, G.R., Pedersen, L., Valente, L., Chatterjee, I., Kinzy, T.G., Kjeldgaard, M., Nyborg, J. (2000) Mol Cell 6: 1261
Crystal structures of nucleotide exchange intermediates in the eEF1A-eEF1Balpha complex Andersen, G.R., Valente, L., Pedersen, L., Kinzy, T.G., Nyborg, J. (2001) Nat Struct Biol 8: 531
Organizational Affiliation:
Department of Molecular Genetics, Microbiology & Immunology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway 08854, USA.
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