The crystal structure of Sulfolobus solfataricus elongation factor 1alpha in complex with GDP reveals novel features in nucleotide binding and exchange.
The crystal structure of elongation factor 1alpha from the archaeon Sulfolobus solfataricus in complex with GDP (SsEF-1alpha.GDP) at 1.8 A resolution is reported. As already known for the eubacterial elongation factor Tu, the SsEF-1alpha.GDP structure consists of three different structural domains. Surprisingly, the analysis of the GDP-binding site reveals that the nucleotide- protein interactions are not mediated by Mg(2+). Furthermore, the residues that usually co-ordinate Mg(2+) through water molecules in the GTP-binding proteins, though conserved in SsEF-1alpha, are located quite far from the binding site. [(3)H]GDP binding experiments confirm that Mg(2+) has only a marginal effect on the nucleotide exchange reaction of SsEF-1alpha, although essential to GTPase activity elicited by SsEF-1alpha. Finally, structural comparisons of SsEF- 1alpha.GDP with yeast EF-1alpha in complex with the nucleotide exchange factor EF-1beta shows that a dramatic rearrangement of the overall structure of EF-1alpha occurs during the nucleotide exchange.
Vitagliano
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L
Centro di Biocristallografia, CNR, via Mezzocannone 6, I-80134 Naples, Italy.
Masullo
M
M
Sica
F
F
Zagari
A
A
Bocchini
V
V
D019843:Archaeal Proteins / Q000737:chemistry*; D001665:Binding Sites; D003461:Crystallography; D006150:Guanine Nucleotides / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000737:chemistry*; D008274:Magnesium; D020648:Peptide Elongation Factor 1 / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D016944:Sulfolobus / Q000737:chemistry*
D019843:Archaeal Proteins; D006150:Guanine Nucleotides; D020648:Peptide Elongation Factor 1; D006153:Guanosine Diphosphate; D008274:Magnesium