Berlin 2018 – scientific programme
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BP: Fachverband Biologische Physik
BP 28: Single Molecule Biophysics
BP 28.7: Talk
Thursday, March 15, 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.