Dresden 2009 – wissenschaftliches Programm
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SYSO: Symposium Self-organizing Surfaces and Interfaces
SYSO 5: Self-Organizing Surfaces and Interfaces IV
SYSO 5.2: Vortrag
Donnerstag, 26. März 2009, 11:15–11:30, GÖR 226
DNA interaction with freestanding cationic lipid bilayers — •Christoph Herold, Eugene P. Petrov, and Petra Schwille — Biophysics, BIOTEC, TU Dresden, Tatzberg 47-51, 01307 Dresden
We study interaction of DNA molecules of different lengths (∼10...50 kbp) with freestanding (giant unilamellar vesicles) and supported cationic lipid bilayers. Upon adsorption on supported cationic bilayers DNA molecules behave as 2D random self-avoiding coils, in agreement with observations previously reported in the literature. A completely different picture is observed when DNA molecules adsorb on freestanding cationic bilayers: In this case, shortly after adsorption, the adsorbed DNA molecules collapse from the coil conformation (gyration radius of ca. 2 µm) into a globule with a size below the optical resolution limit (gyration radius of ca. 0.3 µm). The DNA globules stay attached to the bilayer and exhibit translational Brownian motion on the membrane with a diffusion coefficient of ∼0.6 µm2/s corresponding to the size of ∼100 nm, in agreement with the dimensions expected for globules produced upon DNA condensation. We present results of a systematic study of this phenomenon as a function of the DNA fragment length and cationic lipid membrane composition using fluorescence video microscopy with single particle tracking, transmission electron microscopy, and atomic force microscopy.