Regensburg 2016 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

BP: Fachverband Biologische Physik

BP 3: Protein Structure and Dynamics

BP 3.3: Vortrag

Montag, 7. März 2016, 10:15–10:30, H44

Peptides in Presence of Aqueous Ionic Liquids: Tunable Co-Solutes as Denaturants or Protectants? — Volker Lesch¹, Andreas Heuer¹, Diddo Diddens¹, Christian Holm², and •Jens Smiatek² — ¹Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany — ²Institut für Computerphysik, Universität Stuttgart, D-70569 Stuttgart, Germany

We studied the stability of a small beta-hairpin peptide under the influence of aqueous 1-ethyl-3-methylimidazolium acetate ([EMIM]+ [ACE]-) solution via all-atom molecular dynamics simulations in combination with metadynamics. Our free energy results indicate a denaturation of the peptide structure in presence of the ionic liquid which is validated by a significant broadening of the end-to-end distance. The radial distribution functions between the ions and the peptide were used for the calculation of the preferential binding coefficients in terms of the Kirkwood-Buff theory. A significant structure dependent binding of acetate to the peptide was found which can be interpreted as the main reason for the denaturation of the native conformation. The outcomes of our simulations allow us to propose a simple mechanism to explain the unfolding of the peptide with regard to the specific properties of ionic liquids. Our results are in good agreement with experimental findings and demonstrate the benefits of ionic liquids as tunable co-solutes with regard to their influence on protein structural properties.