Berlin 2015 – scientific programme
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BP: Fachverband Biologische Physik
BP 53: Complex Fluids and Soft Matter (joint BP/DY/CPP)
BP 53.4: Talk
Friday, March 20, 2015, 10:15–10:30, H 1058
Biomolecule dynamics in microfluidic pH gradients and prebiotic FeS membranes — •Friederike M. Möller1, Dominic Berchtold1, Franziska Kriegel1, Laura Barge2, Michael Russell2, and Dieter Braun1 — 1Systems Biophysics, LMU München, Germany — 2Jet Propulsion Laboratory, Pasadena, USA
What are possible driving forces to reduce local entropy in early evolution? Early earth creates a marked redox potential of >600mV between the CO2-dominated atmosphere, creating an ocean around pH 6 and the alkaline outflow of geological serpentinization reactions at pH 10. A rocky FeS membrane forms upon contact from the sulfuric S-- and the Fe++ ions. Its equilibrium version was studied by Huber and Wächtershäuser to form the first organic molecules starting from CO. The FeS clusters created in the membrane are central parts in ancient electron-transfer proteins.
What are the physical characteristics of this membrane? In a microfluidic replica, the pH gradient leaks through the membrane. However, we find yet unexplained attractive forces: hydrophobic and charged molecules are strongly attracted towards the membrane center. As reference system, we create pH gradients in water by uncaging of OH- or H+ ions. The phoretic motions and pH gradients are measured by fluorescence. The rich non-equilibrium dynamics are explained with finite element modeling. They offer a microscopic view back in time into the geological setting of early Earth.