Guanidinium can both Cause and Prevent the Hydrophobic Collapse of Biomacromolecules.

ABSTRACT: A combination of Fourier transform infrared and phase transition measurements as well as molecular computer simulations, and thermodynamic modeling were performed to probe the mechanisms by which guanidinium (Gnd⁺) salts influence the stability of the collapsed versus uncollapsed state of an elastin-like polypeptide (ELP), an uncharged thermoresponsive polymer. We found that the cation's action was highly dependent upon the counteranion with which it was paired. Specifically, Gnd⁺ was depleted from the ELP/water interface and was found to stabilize the collapsed state of the macromolecule when paired with well-hydrated anions such as SO₄^2-. Stabilization in this case occurred via an excluded volume (or depletion) effect, whereby SO₄

SUBMITTER: Heyda J 

PROVIDER: S-EPMC5499822 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature