Berlin 2012 – scientific programme

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BP: Fachverband Biologische Physik

BP 24: Posters: DNA/RNA and Related Enzymes

BP 24.9: Poster

Thursday, March 29, 2012, 17:30–19:30, Poster A

Kinetics of DNA hairpin-loops in crowded and non-crowded fluids — •Olivia Stiehl, Maria Hanulova, Gernot Guigas, and Matthias Weiss — University of Bayreuth, Bayreuth, Germany

Single-stranded DNA hairpin-loops are involved in many biological processes, e.g. in the regulation of gene expression and DNA recombination. Investigating the kinetics of hairpin loops yields a better quantitative understanding of such processes and therefore may help to improve, for instance, the efficiency of antisense drugs. Using a combination of fluorescence correlation spectroscopy and fluorescence energy transfer, we have investigated the kinetics of thermally induced DNA hairpin-loop fluctuations. In particular, we were interested in the influence of macromolecular crowding on the time constant of opening/closing of the DNA loop and on the fraction of open DNA loops. Our measurements were performed with the crowding agent dextran at different concentrations and molecular weights. We found that both, a purely viscous as well as a crowded environment lead to a slower kinetics. Furthermore, our measurements indicate that a viscous surrounding does not affect the fraction of open DNA loops, whereas an increased crowding enhanced the fraction of closed DNA loops.