On the origin of the enthalpy and entropy convergence temperatures in protein folding.
- 1 October 1992
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 89 (19) , 9335-9338
- https://doi.org/10.1073/pnas.89.19.9335
Abstract
Temperature dependence of the thermodynamics of folding/unfolding for cytochrome c has been determined as a function of moderate [0-10% (vol/vol)] concentrations of methanol. Heat capacity change (DELTAC(p)) for unfolding decreases with increased concentrations of methanol, consistent with a higher solvent hydrophobicity. For a given transition temperature, this effect results in higher experimental enthalpy (DELTAH and entropy (DELTAS) changes with increased methanol concentrations. When the enthalpy or entropy data sets obtained at different methanol concentrations are plotted as a function of temperature, they are seen to converge and assume common values around 100-degrees-C for DELTAH and 112-degrees-C for DELTAS. These convergence temperatures are similar to those obtained for different proteins in aqueous solution when DELTAH and DELTAS are normalized with respect to number of residues. It has been previously hypothesized that these convergence temperatures correspond to the temperatures at which the hydrophobic contributions to DELTAH and DELTAS are zero; the results presented here agree with this viewpoint.Keywords
This publication has 23 references indexed in Scilit:
- The molecular basis of cooperativity in protein folding. Thermodynamic dissection of interdomain interactions in phosphoglycerate kinaseBiochemistry, 1992
- Molecular basis of co-operativity in protein foldingJournal of Molecular Biology, 1991
- Solid model compounds and the thermodynamics of protein unfoldingJournal of Molecular Biology, 1991
- Calorimetric determination of the energetics of the molten globule intermediate in protein folding: apo-.alpha.-lactalbuminBiochemistry, 1991
- Characterization of a partially denatured state of a protein by two-dimensional NMR: reduction of the hydrophobic interactions in ubiquitinBiochemistry, 1991
- Heat capacity of proteinsJournal of Molecular Biology, 1990
- A simple model for proteins with interacting domains. Applications to scanning calorimetry dataBiochemistry, 1989
- A thermodynamic approach to the problem of stabilization of globular protein structure: A calorimetric studyJournal of Molecular Biology, 1974
- Enthalpy change accompanying the oxidation of ferrocytochrome c in the pH range 6-11 at 25°Biochemistry, 1969
- Thermodynamics of protein denaturation. III. Denaturation of ribonuclease in water and in aqueous urea and aqueous ethanol mixturesJournal of the American Chemical Society, 1967