SKM 2023 – scientific programme

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BP: Fachverband Biologische Physik

BP 29: Statistical Physics of Biological Systems II (joint session BP/DY)

BP 29.8: Talk

Friday, March 31, 2023, 11:30–11:45, BAR Schö

Multivalent binding proteins can drive collapse and reswelling of chromatin in confinement — •Sougata Guha and Mithun K. Mitra — Department of Physics, IIT Bombay, India

Collapsed conformations of chromatin have been long suspected of being mediated by interactions with multivalent binding proteins, which can bring together distant sections of the chromatin fiber. In this study, we use Langevin dynamics simulation of a coarse grained chromatin polymer to show that the role of binding proteins can be more nuanced than previously suspected. In particular, for chromatin polymer in confinement, entropic forces can drive reswelling of collapsed chromatin with increasing binder concentrations, and this reswelling transition happens at physiologically relevant binder concentrations. Both the extent of collapse, and also of reswelling depends on the strength of confinement. We also study the kinetics of collapse and reswelling and show that both processes occur in similar timescales. We characterise this reswelling of chromatin in biologically relevant regimes and discuss the non-trivial role of multivalent binding proteins in mediating the spatial organisation of the genome.