PROTEIN STABILITYPrecision Analysis, Accelerated Discovery

Protein conformational stability is governed by a small folding–unfolding free-energy difference, often only on the order of a few kcal/mol. Because that margin is narrow, proteins can be sensitive to temperature, pH, ionic environment, pressure, cosolutes, and interfaces. A useful way to frame the field is that heat denaturation and cold denaturation are two limbs of the same stability curve: high temperature can drive unfolding through increased conformational entropy and weakened hydrophobic stabilization, whereas sufficiently low temperature can also destabilize folded structure through changes in hydration and heat-capacity effects. Importantly, the intermediates populated on the cold and hot limbs need not be identical; partially folded or "molten-globule-like" states may be especially relevant near cold-denaturation conditions.