Unfolding of hydrophobic polymers in guanidinium chloride solutions.

摘要: Guanidinium chloride (GdmCl) is a widely used chemical denaturant that unfolds proteins. Its effects on hydrophobic interactions are, however, not fully understood. We quantify the of GdmCl various manifestations hydrophobicity--from solvation and small solutes to folding-unfolding polymers--in water in concentrated solutions. For comparison, we also perform similar calculations solutions NaCl CsCl water. Like CsCl, increases surface tension water, decreases solubility solutes, enhances strength at pair level. However, unlike destabilizes folded states polymers. show Gdm(+) ions preferentially coat polymer, it direct van der Waals interaction between polymer contributes destabilization states. Interestingly, temperature dependence free energy unfolding protein-like, with signatures both heat cold denaturation. Addition shifts denaturation higher, into experimentally accessible region. Finally, translational as well conformational dynamics are slower correlate molecules solution.