The thermodynamics of the unfolding of an isolated protein subdomain. The 255-316 C-terminal fragment of thermolysin.
Differential scanning calorimetry has been used to study the thermal unfolding of the 255-316 C-terminal fragment of thermolysin. The concentration effect on the calorimetric transitions of the fragment in 0.1 M NaCl and 20 mM phosphate buffer, pH 7.5, shows that it behaves as a highly stable dimer in solution, within the concentration range 0.19-4.55 mg/ml, undergoing a reversible two-state thermal unfolding process. The thermodynamic parameters of unfolding (delta G = 60 +/- 6 kJ/(mol of dimer) at 20 degrees C) are similar to those normally observed for small, compact, globular proteins. This and previous studies [1989, Eur. J. Biochem. 180, 513-518] show that the 255-316 fragment folds into a stable, native-like globular structure.
Conejero-Lara
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Department of Physical Chemistry, Faculty of Sciences, University of Granada, Spain.
De Filippis
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Fontana
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Mateo
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PL
D002152:Calorimetry, Differential Scanning; D004795:Enzyme Stability; D046911:Macromolecular Substances; D010446:Peptide Fragments / Q000737:chemistry*; D017510:Protein Folding; D012996:Solutions; D013816:Thermodynamics; D013820:Thermolysin / Q000737:chemistry*
D046911:Macromolecular Substances; D010446:Peptide Fragments; D012996:Solutions; D013820:Thermolysin