title: Thermal stability of proteins does not correlate with the energy of intramolecular interactions.
abstract: Small monomeric proteins from mesophilic and thermophilic organisms were studied. They have close structural and physical and chemical properties but vary in thermal stability. A thermodynamic analysis of heat unfolding was made and integral enthalpy of unfolding (DeltaH(unf)), heat capacity of hydration (DeltaC(p)(hyd)) and enthalpy of hydration (DeltaH(hyd)) and of the buried surface area (DeltaASA) of nonpolar and polar groups as well as the enthalpy of disruption of intramolecular interaction (DeltaH(int) in gas phase) at 298 K were determined. The absence of correlation between protein thermostability and energetic components suggests that regulatory mechanism of protein thermal stabilization has entropic nature.
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia. nikolay@icb.psn.ru
authors.forename: Nikolay N
authors.initials: NN
authors.lastname: Khechinashvili
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Volchkov
authors.forename: Artem V
authors.initials: AV
authors.lastname: Kabanov
authors.forename: Guido
authors.initials: G
authors.lastname: Barone
mesh_terms: D003890:Desiccation; D004734:Energy Metabolism; D006860:Hydrogen Bonding; D008956:Models, Chemical; D011489:Protein Denaturation; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D013696:Temperature; D013816:Thermodynamics
chemical_list: D011506:Proteins