The solution structure of the guanine nucleotide exchange domain of human elongation factor 1beta reveals a striking resemblance to that of EF-Ts from Escherichia coli.
Perez, J.M., Siegal, G., Kriek, J., Hard, K., Dijk, J., Canters, G.W., Moller, W.(1999) Structure 7: 217-226
- PubMed: 10368288 
- DOI: https://doi.org/10.1016/s0969-2126(99)80027-6
- Primary Citation of Related Structures:  
1B64 - PubMed Abstract: 
In eukaryotic protein synthesis, the multi-subunit elongation factor 1 (EF-1) plays an important role in ensuring the fidelity and regulating the rate of translation. EF-1alpha, which transports the aminoacyl tRNA to the ribosome, is a member of the G-protein superfamily. EF-1beta regulates the activity of EF-1alpha by catalyzing the exchange of GDP for GTP and thereby regenerating the active form of EF-1alpha. The structure of the bacterial analog of EF-1alpha, EF-Tu has been solved in complex with its GDP exchange factor, EF-Ts. These structures indicate a mechanism for GDP-GTP exchange in prokaryotes. Although there is good sequence conservation between EF-1alpha and EF-Tu, there is essentially no sequence similarity between EF-1beta and EF-Ts. We wished to explore whether the prokaryotic exchange mechanism could shed any light on the mechanism of eukaryotic translation elongation. Here, we report the structure of the guanine-nucleotide exchange factor (GEF) domain of human EF-1beta (hEF-1beta, residues 135-224); hEF-1beta[135-224], determined by nuclear magnetic resonance spectroscopy. Sequence conservation analysis of the GEF domains of EF-1 subunits beta and delta from widely divergent organisms indicates that the most highly conserved residues are in two loop regions. Intriguingly, hEF-1beta[135-224] shares structural homology with the GEF domain of EF-Ts despite their different primary sequences. On the basis of both the structural homology between EF-Ts and hEF-1beta[135-224] and the sequence conservation analysis, we propose that the mechanism of guanine-nucleotide exchange in protein synthesis has been conserved in prokaryotes and eukaryotes. In particular, Tyr181 of hEF-1beta[135-224] appears to be analogous to Phe81 of Escherichia coli EF-Ts.
Organizational Affiliation: 
Department of Molecular Cell Biology, Sylvius Laboratory, University ofLeiden, Wassenaarseweg 72 NL-2333, AL Leiden, The Netherlands.