Role of electrostatics in the thermal stability of ubiquitin - A combined DSC and MM study

The failure of the ubiquitin-proteasome system is involved in many diseases. Here, in order to assess the pH-induced changes in the physico-chemical properties of ubiquitin, DSC measurements have been carried out at 2.5 < pH < 7. Parallel 'in silico' pH titrations, suggest that there is a direct relationship between the calorimetric data and the electrostatic properties of ubiquitin. It is suggested that these pH-induced changes in the properties of ubiquitin may play a role in determining its ability to properly conjugate with its physiological targets.