This is because hydrogen-bonding groups in an unfolded protein form hydrogen bonds with water molecules. Thus the contribution of a hydrogen bond to the stability of a native protein is the small difference in hydrogen bonding free energies between the native and unfolded states (−2 to 8 kJ ∙ mol−1)
#Unit 1. Molecules and their Interaction Relevant to Biology#Protein Stability & Folding#Part B Pointers
