Berlin 2015 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 44: DNA/RNA and related enzymes

BP 44.7: Vortrag

Donnerstag, 19. März 2015, 16:45–17:00, H 1058

Continuous, sequence dependent gelation of nucleic acids driven by a thermal gradient. — •Christof Mast, Matthias Morasch, and Dieter Braun — Systems Biophysics, Faculty of Physics, LMU Munich, Amalienstrasse 54, 80799 Munich

Under equilibrium conditions, the phase transition of bio-polymers like DNA toward a compacted state requires mutual binding forces from high polymer concentrations or multivalent ions. We demonstrate that the physical non-equilibrium of a thermal gradient across an elongated chamber accomplishes this task from dilute DNA solutions without the help of multivalent ions, proteins, evaporation or encapsulation. The gelation process is governed by the base pair interactions between respective DNA strands, leading to a highly nonlinear sequence dependency of the gelation process. DNA of different sequences are compacted at distinct sites, yielding a sequence-based physical sorting mechanism. DNA strands with low hybridization energies do not form a gel within the measurement time. The DNA gel is continuously rebuilt inside the thermal gradient in a dynamic turn-over fashion and remains stable for days under dilute equilibrium conditions. The process implements a basic prebiotic machine that selects and stores sticky sequence motifs out of a random sequence pool.