Guanidine-induced unfolding of the Sso7d protein from the hyperthermophilic archaeon Sulfolobus solfataricus.
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.
Granata
Vincenzo
V
Dipartimento di Chimica, Università di Napoli Federico II, Via Cinthia, 45-80126 Napoli, Italy.
Vecchio
Pompea Del
PD
Barone
Guido
G
Shehi
Erlet
E
Fusi
Paola
P
Tortora
Paolo
P
Graziano
Giuseppe
G
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*
D019843:Archaeal Proteins; D004268:DNA-Binding Proteins; C093228:Sso7d protein, Sulfolobus; D019791:Guanidine