title: The magic spot ppGpp influences in vitro the molecular and functional properties of the elongation factor 1α from the archaeon Sulfolobus solfataricus.
abstract: Guanosine tetra-phosphate (ppGpp), also known as "magic spot I", is a key molecule in the stringent control of most eubacteria and some eukarya. Here, we show that ppGpp affects the functional and molecular properties of the archaeal elongation factor 1α from Sulfolobus solfataricus (SsEF-1α). Indeed, ppGpp inhibited archaeal protein synthesis in vitro, even though the concentration required to get inhibition was higher than that required for the eubacterial and eukaryal systems. Regarding the partial reactions catalysed by SsEF-1α the effect produced by ppGpp on the affinity for aa-tRNA was lower than that measured in the presence of GTP but higher than that for GDP. Magic spot I was also able to bind SsEF-1α with an intermediate affinity in comparison to that displayed by GDP and GTP. Furthermore, ppGpp inhibited the intrinsic GTPase of SsEF-1α with a competitive behaviour. Finally, the binding of ppGpp to SsEF-1α rendered the elongation factor more resistant to heat treatment and the analysis of the molecular model of the complex between SsEF-1α and ppGpp suggests that this stabilisation arises from the charge optimisation on the surface of the protein.
authors: Dipartimento di Studi delle Istituzioni e dei Sistemi Territoriali, Università degli Studi di Napoli Parthenope, Via Medina 40, 80133 Naples, Italy.
authors: Nicola M
authors: NM
authors: Martucci
authors: Anna
authors: A
authors: Lamberti
authors: Luigi
authors: L
authors: Vitagliano
authors: Piergiuseppe
authors: P
authors: Cantiello
authors: Immacolata
authors: I
authors: Ruggiero
authors: Paolo
authors: P
authors: Arcari
authors: Mariorosario
authors: M
authors: Masullo
mesh_terms: D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D006159:Guanosine Tetraphosphate / Q000235:genetics / Q000378:metabolism*; D020648:Peptide Elongation Factor 1 / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000502:physiology*; D019642:RNA, Archaeal / Q000235:genetics / Q000378:metabolism; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics / Q000378:metabolism; D048229:Sulfolobus solfataricus / Q000235:genetics / Q000378:metabolism*
chemical_list: D019843:Archaeal Proteins; D020648:Peptide Elongation Factor 1; D019642:RNA, Archaeal; D012346:RNA, Transfer, Amino Acyl; D006159:Guanosine Tetraphosphate