Berlin 2018 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 28: Single Molecule Biophysics

BP 28.7: Vortrag

Donnerstag, 15. März 2018, 11:30–11:45, H 1058

Pressure effect on the conformational landscapes of a large loop DNA hairpin in the presence of osmolyte and salt — Satyajit Patra¹, Vitor Schuabb¹, •Irena Kiesel¹, Jim Marcel Knop¹, Rosario Oliva², and Roland Winter¹ — ¹Fakultät für Chemie und Chemische Biologie, TU Dortmund, Otto-Hahn-Str. 6 — ²Department of chemical sciences, University of Naples Federico II, Via Cinita, 80126 Naples, Italy

The conformational landscapes of a large loop DNA hairpin model system has been investigated in absence and presence of salt and osmolytes at both ambient and extreme conditions (high hydrostatic pressure and high temperature) using primarily single molecule Förster resonance energy transfer (smFRET) technique. We use cationic salts (K⁺, Mg²⁺, Co³⁺) and TMAO and urea as osmolytes. Introduction of pressure favors the open state (low FRET species) of this DNA hairpins thus facilitates the unfolding. Addition of the salt in the solution populates the high FRET species and counteract the pressure and temperature effect. The order of stabilizing effect of the salt against pressure and temperature follows the order Co³⁺ > Mg²⁺ > K⁺. Introduction of urea and temperature favors the formation of intermediate state populations which is further supported by smFRET measurement under immobilized condition. This is indicating that the free energy landscapes of this large loop DNA hairpin is actually a rugged one. Further smFRET measurement under immobilized condition provides a deeper insights into the differential stabilization mechanism of salt and osmolytes.