Solvation and solubility of globular proteins

The solvation Gibbs energy of a globular protein is expressed in terms of its various ingredients. Estimating each of these ingredients leads to an estimate of the overall solvation Gibbs energy of globular protein. As expected, the contribution of the sum of all the hydrophilic groups on the surface of the protein makes the solvation Gibbs energy of the protein less positive. However, this may not be enough to make the solvation Gibbs energy negative. We found, quite unexpectedly, that correlations between pairs and triplets of hydrophilic groups substantially decrease the solvation Gibbs energy of the protein. Therefore we conclude that pair and higher order correlations between hydrophilic groups on the surface of the protein has a significant contribution to the high solubility of globular proteins.