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BP: Fachverband Biologische Physik

BP 44: Biomaterials and Biopolymers (Joint Session BP/CPP)

BP 44.3: Vortrag

Mittwoch, 22. März 2017, 15:30–15:45, SCH A251

Guanidinium Salts Can both Cause and Prevent the Hydrophobic Collapse of Biomacromolecules — •Jan Heyda^1,2, Halil Okur³, Joachim Dzubiella^2,4, Pavel Jungwirth⁵, and Paul Cremer^3,6 — ¹Physical Chemistry Department, UCT Prague, Czech Republic — ²Institut für Weiche Materie und Funktionale Materialien, HZB Berlin, Germany — ³Chemistry Department, Penn. State University, Pennsylvania, USA — ⁴Institut für Physik, HU Berlin, Germany — ⁵Institute of Organic Chemistry and Biochemistry, CAS, Prague, Czech Republic — ⁶Biochemistry and Molecular Biology Department, Penn. State University, Pennsylvania, USA

A combination of experimental methods with theory and simulations were performed to probe the mechanisms by which guanidinium (Gnd⁺) salts influence the stability of the collapsed vs. uncollapsed state of an elastin-like polypeptide (ELP). The Gnd⁺ action was found highly dependent upon its counteranion, resulting in three distinct physical regimes. (1) Well-hydrated Gnd₂SO₄ salt was depleted from the ELP/water interface and was found to stabilize the collapsed state of the macromolecule. (2) Salts (e.g. GndSCN), which interacted very strongly with the polymer, stabilized the collapsed state at low salt concentrations, when both ions were found to be enriched in the collapsed state of the polymer. The collapsed state is stabilized due to crosslinking of the polymer chains. At higher salt concentrations, the same strong salt-polymer interaction results in stabilization of the uncollapsed state. (3) GndCl interacted in an intermediate fashion favored the uncollapsed state at all salt concentrations.