Water, hydrophobic interaction, and protein stability

C. GASTÓN FERRARA; J. RAÚL GRIGERA

Budapest

Conferencia; 8th EBSA European Biophysics Congress; 2011

European Biophysics

Although there are several forces maintaining protein structure, it is well know that hydrophobic interaction is the dominant force of protein folding. Then, we can infer that any factor that alters hydrophobic interaction will affect the protein stability. We have study by computer simulationa model system consisting in solution of Lenard-Jones particles in water (SPC/E model) at different pressures and temperatures and analyzed the solubility i.e. the aggregation properties, of such a system. From theobtained data we are able to build up the phase surface determining the critical point. The computing results where compared with experimental data of binary mix of non polar substance in water and of protein denaturation, finding high coincidence on the critical point. Since the behavior of ourmodel system can only be due to hydrophobic effects, the coincidences with the denaturation of proteins allow us to conclude that the dominant factor that determine temperature and pressure denaturation of proteins is thehydrophobic interaction. The temperature and pressures at which the denaturation, as well the disaggregation of simple non-polar particles, starts agree with what we could expect based on the cross over line of the low to high density structure water transition.