Sommaire:

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 and the residence time in an occupancy state.

Here, we present a general-purpose grand canonical Hamiltonian description of a small one-dimensional (1D) lattice gas with nearest-neighbor interactions as a prototypical example of cooperativity-influenced adsorption processes, allowing us to elucidate how the strength of the interaction potential between neighboring bound particles determines the intensity of the fluctuations of the mean occupancy.

Then, we study how said interaction affects the out-of-equilibrium properties of a binding-unbinding process from a substrate, looking into the characteristic relaxation times to the equilibrium state and the dwell times of bound particles.

Finally, we 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 and estimate the value of the interaction potential.

This work provides a step forward in the understading of the role of cooperativity in the adaptability of small molecular systems such as the bacterial flagellar motor.

Pour plus d'informations, merci de contacter Franco-oñate M.-J.