title: Guanidine-induced unfolding of the Sso7d protein from the hyperthermophilic archaeon Sulfolobus solfataricus.
abstract: The unfolding induced by guanidine hydrochloride of the small protein Sso7d from the hyperthermophilic archaeon Sulfolobus solfataricus has been investigated by means of circular dichroism and fluorescence measurements. At neutral pH and room temperature the midpoint of the transition occurred at 4M guanidine hydrochloride. Thermodynamic information was obtained by means of both the linear extrapolation model and the denaturant binding model, in the assumption of a two-state N<==>D transition. A comparison with thermodynamic data determined from the thermal unfolding of Sso7d indicated that the denaturant binding model has to be preferred. Finally, it is shown that Sso7d is the most stable against both temperature and guanidine hydrochloride among a set of globular proteins possessing a very similar 3D structure.
authors.affiliation: Dipartimento di Chimica, Università di Napoli Federico II, Via Cinthia, 45-80126 Napoli, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Granata
authors.forename: Pompea Del
authors.initials: PD
authors.lastname: Vecchio
authors.forename: Guido
authors.initials: G
authors.lastname: Barone
authors.forename: Erlet
authors.initials: E
authors.lastname: Shehi
authors.forename: Paola
authors.initials: P
authors.lastname: Fusi
authors.forename: Paolo
authors.initials: P
authors.lastname: Tortora
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Graziano
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry*; D002942:Circular Dichroism; D004268:DNA-Binding Proteins / Q000737:chemistry*; D019791:Guanidine / Q000737:chemistry*; D011489:Protein Denaturation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D013050:Spectrometry, Fluorescence; D048229:Sulfolobus solfataricus / Q000737:chemistry*
chemical_list: D019843:Archaeal Proteins; D004268:DNA-Binding Proteins; C093228:Sso7d protein, Sulfolobus; D019791:Guanidine