-transparent.png){kind=logo}
The beta-glycosidase isolated from the extreme thermophilic archaeon Sulfolobus solfataricus, grown at 87 degrees C, is a tetrameric protein with a molecular mass of 240 kDa. This enzyme is barely active at 30 degrees C and has optimal activity, over 95 degrees C, at pH 6.5. Its thermal stability was investigated at pH 10.1 and 10.6 by means of functional studies, circular dichroism and differential scanning calorimetry. There was no evidence of thermal activation of the enzyme and the temperature-induced denaturation was irreversible and not well represented by the two-state transition model. A more complex process occurred, involving the dissociation and unfolding of subunits, and subsequent nonspecific association and/or aggregation. Denaturation temperature was around 85 degrees C, depending on protein concentration. The denaturation enthalpy change was between 7,500 and 9,800 kJ.mol-1, depending on the pH. The collapse of the native structure around 85 degrees C was confirmed by circular dichroism measurements and time-dependent activity studies. Finally, preliminary investigations were performed on the recombinant enzyme expressed in Escherichia coli.
S D'Auria, and
M Rossi, and
G Barone, and
F Catanzano, and
P Del Vecchio, and
G Graziano, and
R Nucci
January 2001,
Methods in enzymology,
S D'Auria, and
M Rossi, and
G Barone, and
F Catanzano, and
P Del Vecchio, and
G Graziano, and
R Nucci
December 2001,
FEBS letters,
S D'Auria, and
M Rossi, and
G Barone, and
F Catanzano, and
P Del Vecchio, and
G Graziano, and
R Nucci
February 2000,
Journal of biotechnology,
S D'Auria, and
M Rossi, and
G Barone, and
F Catanzano, and
P Del Vecchio, and
G Graziano, and
R Nucci
January 2006,
Biochemistry,
S D'Auria, and
M Rossi, and
G Barone, and
F Catanzano, and
P Del Vecchio, and
G Graziano, and
R Nucci
December 1996,
Protein engineering,
S D'Auria, and
M Rossi, and
G Barone, and
F Catanzano, and
P Del Vecchio, and
G Graziano, and
R Nucci
May 1996,
Protein expression and purification,
S D'Auria, and
M Rossi, and
G Barone, and
F Catanzano, and
P Del Vecchio, and
G Graziano, and
R Nucci
June 2003,
Biochemical and biophysical research communications,
S D'Auria, and
M Rossi, and
G Barone, and
F Catanzano, and
P Del Vecchio, and
G Graziano, and
R Nucci
September 1994,
Protein science : a publication of the Protein Society,
S D'Auria, and
M Rossi, and
G Barone, and
F Catanzano, and
P Del Vecchio, and
G Graziano, and
R Nucci
June 2004,
International journal of biological macromolecules,
S D'Auria, and
M Rossi, and
G Barone, and
F Catanzano, and
P Del Vecchio, and
G Graziano, and
R Nucci
November 1995,
Enzyme and microbial technology,
