title: The entropic nature of protein thermal stabilization.
abstract: We performed thermodynamic analysis of temperature-induced unfolding of mesophilic and thermophilic proteins. It was shown that the variability in protein thermostability associated with pH-dependent unfolding or linked to the substitution of amino acid residues on the protein surface is evidence of the governing role of the entropy factor. Numerical values of conformational components in enthalpy, entropy and free energy which characterize protein unfolding in the "gas phase" were obtained. Based on the calculated absolute values of entropy and free energy, a model of protein unfolding is proposed in which the driving force is the conformational entropy of native protein, as an energy of the heat motion (T·S(NC)) increasing with temperature and acting as an factor devaluating the energy of intramolecular weak bonds in the transition state.
authors.affiliation: a Institute of Cell Biophysics, Russian Academy of Sciences , Pushchino, Moscow Region 142290 , Russia .
authors.forename: Nikolay N
authors.initials: NN
authors.lastname: Khechinashvili
authors.forename: Artem V
authors.initials: AV
authors.lastname: Capital Ka Cyrillicabanov
authors.forename: Maxim S
authors.initials: MS
authors.lastname: Kondratyev
authors.forename: Robert V
authors.initials: RV
authors.lastname: Polozov
mesh_terms: D019277:Entropy; D006358:Hot Temperature; D008958:Models, Molecular; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D055550:Protein Stability; D011506:Proteins / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D011506:Proteins
keywords: absolute entropy; absolute free energy; protein thermostability; protein unfolding