1b64
SOLUTION STRUCTURE OF THE GUANINE NUCLEOTIDE EXCHANGE FACTOR DOMAIN FROM HUMAN ELONGATION FACTOR-ONE BETA, NMR, 20 STRUCTURES
OverviewOverview
BACKGROUND: 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. RESULTS: 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. CONCLUSIONS: 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.
About this StructureAbout this Structure
1B64 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
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 JM, Siegal G, Kriek J, Hard K, Dijk J, Canters GW, Moller W, Structure. 1999 Feb 15;7(2):217-26. PMID:10368288 Page seeded by OCA on Fri May 2 11:07:05 2008