Regensburg 2016 – wissenschaftliches Programm

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

BP: Fachverband Biologische Physik

BP 24: Posters - Single Molecule Biophysics

BP 24.4: Poster

Montag, 7. März 2016, 17:30–19:30, Poster C

Nanomechanics of Fluorescent DNA-Dyes on DNA investigated by Magnetic Tweezers — •Ying Wang, Andy Sischka, Volker Walhorn, Katja Tönsing, and Dario Anselmetti — Experimental Biophysics and Applied Nanoscience, Physics Department, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany

Fluorescent DNA-dyes are broadly used in many biotechnological applications for detecting and imaging DNA in cells and gels. Their specific and selective interaction alters the structural and nanomechanical properties of DNA and affects biological processes that are associated with it. Although interaction modes like intercalation and minor grove binding already have been identified, associated mechanic effects like local elongation, unwinding, and softening of the DNA often remain poorly understood. We used magnetic tweezers in order to quantitatively investigate the impact of three DNA-binding dyes (YOYO-1, DAPI and DRAQ5) in a concentration dependent manner. By extending and overwinding individual, torsionally constrained, nick-free dsDNA molecules, we measured the contour lengths and molecular forces which allow estimation of several thermodynamic and nanomechanical binding parameters. Whereas for YOYO-1 and DAPI the binding mechanisms could be allocated to bis-intercalation and minor groove binding, respectively, DRAQ5 exhibited both binding modes in a concentration dependent manner.