Fluctuations in in vivo reactive systems.
Hélène Berthoumieux (LPTMC – Université Pierre & Marie Curie, Paris)
SPECIAL LOCATION (due to renovation work at LPS)
For a chemist, a living cell is a reactive system in which the concentrations of biomolecules are not determined by the thermodynamics but are controlled by energy sources maintaining the system in an out-of-equilibrium state. Chemical reaction networks are thus perturbed by a thermal noise and the fluctuations of these energy sources. Theoretical and experimental studies have shown that the fluctuations of in vivo systems break the fluctuation-dissipation theorem, which is a result of statistical physics at equilibrium. One can thus ask what information is contained in the correlation functions of protein concentrations and how they relate to the response of the reactive network to a perturbation. Answers to these questions are of prime importance to extract meaningful parameters from the in vivo fluorescence correlation spectroscopy data. Here, we present a theoretical study of the fluctuations of the concentration of a reactive species involved in a cyclic network that is in a non-equilibrium steady state perturbed by a noisy force, taking into account both the breaking of detailed balance and extrinsic noises that are known to be important in a cell.