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DY: Fachverband Dynamik und Statistische Physik
DY 53: Statistical Physics of Biological Systems III (joint session BP/DY)
DY 53.4: Talk
Friday, March 22, 2024, 10:30–10:45, H 2032
Signature of (anti)cooperativity in the stochastic fluctuations of small systems: application to the bacterial flagellar motor — •María-José Franco-Oñate1, Andrea Parmeggiani2, Jérôme Dorignac2, Frédéric Geniet2, Jean-Charles Walter2, Francesco Pedaci3, Ashley Nord3, John Palmeri2, and Nils-Ole Walliser2 — 1MPI Physics of Complex Systems, Dresden, Germany — 2Laboratoire Charles Coulomb (L2C), Montpellier, France — 3Centre de Biologie Structurale (CBS), Montpellier, France
The cooperative binding of molecular agents onto a substrate is pervasive in living systems. To study whether a system shows cooperativity, one can rely on the fluctuation analysis of quantities such as the number of substrate-bound units.
Using a general-purpose grand canonical Hamiltonian description of a small one-dimensional (1D) lattice gas with nearest-neighbour interactions as a prototypical example of a cooperativity-influenced adsorption processes, we elucidate how the strength of the interaction potential between neighbouring bound particles on the lattice determines the intensity of the fluctuations of the mean occupancy at steady state.
We then employ this relationship to compare the theoretical predictions of our model to data from single molecule experiments on bacterial flagellar motors (BFM). In this way, we find evidence that cooperativity controls the mechano-sensitive dynamical assembly of the torque-generating units, the so-called stators, onto the BFM.
Keywords: Bacterial flagellar motor; Lattice gas; Fluctuations; Small system