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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 11: Focus: Phase Separation in Biological Systems I (joint session BP/CPP)

CPP 11.8: Vortrag

Montag, 16. März 2020, 12:00–12:15, SCH A251

Sequence dependent gelation, accumulation and sedimentation — •Alexandra Kühnlein¹, Christof Mast¹, Hannes Mutschler², and Dieter Braun¹ — ¹Biophysics and Center for NanoScience, LMU Munich, Amalienstrasse 54, 80799 München — ²Max Planck Institute of Biochemistry, Martinsried, Germany

The origins of biological information constitutes a major challenge for understanding the origins of life. Under Darwinian evolution, a localized, homogeneous sequence phenotype is selected. How could this state of matter emerge from random sequence mixtures?

To jumpstart Darwinian evolution, a random mixture of sequences have to show physical phenotypes, most likely in non-equilibrium settings. We show preliminary results that indicate a self-selection of sequences by cooperative binding.

Eight 80mer sequences, derived from tRNA to implement a hybridization-based replicator, revealed upon cooling a sharp transition to hydrogels with the size of millimeters. These agglomerates, if broken up by flow, sediment under gravity. If one of the eight sequences are missing, no significant gelation and no sedimentation is found.

Secondly, we subjected random sequences to steep thermal gradients where convection and thermophoresis lead to a size-dependent accumulation. By sequencing, we found that the initial random sequence pool accumulated end sequences with a higher affinity for binding. We speculate that in the long run, only a small number of cooperative binding sequences could remain in such a non-equilibrium setting.