title: The crystal structure of Sulfolobus solfataricus elongation factor 1alpha in complex with GDP reveals novel features in nucleotide binding and exchange.
abstract: 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.
authors.affiliation: Centro di Biocristallografia, CNR, via Mezzocannone 6, I-80134 Naples, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Vitagliano
authors.forename: M
authors.initials: M
authors.lastname: Masullo
authors.forename: F
authors.initials: F
authors.lastname: Sica
authors.forename: A
authors.initials: A
authors.lastname: Zagari
authors.forename: V
authors.initials: V
authors.lastname: Bocchini
mesh_terms: 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*
chemical_list: D019843:Archaeal Proteins; D006150:Guanine Nucleotides; D020648:Peptide Elongation Factor 1; D006153:Guanosine Diphosphate; D008274:Magnesium