Mg2+ and a key lysine modulate exchange activity of eukaryotic translation elongation factor 1B alphaPittman, Y.R., Valente, L., Jeppesen, M.G., Andersen, G.R., Patel, S., Kinzy, T.G.
(2006) J.Biol.Chem. 281: 19457-19468
- PubMed: 16675455
- DOI: 10.1074/jbc.M601076200
- Primary Citation of Related Structures:
- PubMed Abstract:
- 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.Mol.Biol. 8: 531
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 ...
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.
Department of Molecular Genetics, Microbiology & Immunology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway 08854, USA.