title: Stability against temperature of Sulfolobus solfataricus elongation factor 1 alpha, a multi-domain protein.
abstract: The elongation factors (EF-Tu/EF-1 alpha) are universal proteins, involved in protein biosynthesis. A detailed characterization of the stability against temperature of SsEF-1 alpha, a three-domain protein isolated from the hyperthermophilic archaeon Sulfolobus solfataricus is presented. Thermal denaturation of both the GDP-bound (SsEF-1 alpha*.GDP) and the ligand-free (nfSsEF-1 alpha) forms was investigated by means of circular dichroism and fluorescence measurements, over the 4.0-7.5 pH interval. Data indicate that the unfolding process is cooperative with no intermediate species and that the few inter-domain contacts identified in the crystal structure of SsEF-1 alpha play a role also at high temperatures. Finally, it is shown that the enzyme exhibits two different interchangeable thermally denatured states, depending on pH.
authors.affiliation: Dip. delle Scienze Biologiche, Sez. di Biostrutture, Università degli Studi di Napoli Federico II, Napoli, Italy. vincenzo_granata@virgilio.it
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Granata
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Graziano
authors.forename: Alessia
authors.initials: A
authors.lastname: Ruggiero
authors.forename: Gennaro
authors.initials: G
authors.lastname: Raimo
authors.forename: Mariorosario
authors.initials: M
authors.lastname: Masullo
authors.forename: Paolo
authors.initials: P
authors.lastname: Arcari
authors.forename: Luigi
authors.initials: L
authors.lastname: Vitagliano
authors.forename: Adriana
authors.initials: A
authors.lastname: Zagari
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000378:metabolism; D002942:Circular Dichroism; D006153:Guanosine Diphosphate / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D020648:Peptide Elongation Factor 1 / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D048229:Sulfolobus solfataricus / Q000378:metabolism*; D013696:Temperature
chemical_list: D019843:Archaeal Proteins; D020648:Peptide Elongation Factor 1; D006153:Guanosine Diphosphate