Regensburg 2013 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 15: DNA/RNA and related enzymes

BP 15.7: Vortrag

Dienstag, 12. März 2013, 13:45–14:00, H43

Towards Darwinian Molecular Evolution in a Thermal Trap — Christof Mast¹, •Severin Schink², Ulrich Gerland², and Dieter Braun¹ — ¹Systems Biophysics, LMU Munich, Germany — ²ASC for Theoretical Physics, LMU Munich, Germany

The formation of polymers such as RNA and their replication is essential for the emergence of life. According to the RNA-world hypothesis the first polymerases were basic RNA strands of several hundred bases. Even with the help of surface catalysis and high monomer concentrations no polymerization of RNA longer than 20 bases could be demonstrated using prebiotic chemistry. Replication reactions are avoided by template inhibition and dilution. Thermal traps can overcome both problems: Temperature gradients in porous rock locally enhance the polymer concentration exponentially better for longer polymers. Since the mean polymer length depends on its local concentration, polymerization and trapping are mutually self-enhanced leading to a hyper-exponential escalation of polymer length. The theory is experimentally confirmed with sticky ended DNA. An extrapolation to the RNA world shows that a short 5 cm crack is likely to generate 100mers of RNA with micromolar concentrations even under unfavorable conditions. We experimentally show that thermals traps can drive exponential replication reactions: Convective flow drives a PCR while concurrent thermophoresis accumulates the replicated 143bp DNA and prevents the diffusion into the bulk solution. The time constant for accumulation is 92s while DNA is doubled every 50s.