Berlin 2018 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 45: Statistical Physics in Biological Systems (joint session DY/BP)

DY 45.11: Talk

Wednesday, March 14, 2018, 12:45–13:00, BH-N 333

Thermodynamically Consistent Coarse Graining of Biocatalysts beyond Michaelis--Menten — •Artur Wachtel, Riccardo Rao, and Massimiliano Esposito — Physics and Materials Science Research Unit, University of Luxembourg, Luxembourg

Virtually all processes in living cells involve catalytic molecules to enhance chemical reactions: various enzymes process metabolites and signaling molecules, catalytically active membrane proteins serve as transporters or receptors for chemical signals.

In this talk we start from the detailed catalytic mechanism of a single biocatalyst and we provide a coarse-graining procedure which, by construction, is thermodynamically consistent even out of equilibrium: This procedure provides stoichiometries, reaction fluxes (kinetic rate laws), and reaction forces (Gibbs energies of reaction) for the coarse-grained level. It can treat active transporters and molecular machines, and thus extends the applicability of ideas that originated in enzyme kinetics. We thus identify the conditions under which a relation between one-way fluxes and forces holds at the coarse-grained level as it holds at the detailed level. In doing so, we clarify the speculations and broad claims made in the literature about such a general flux--force relation. As a further consequence we show that, in contrast to common belief, the second law of thermodynamics does not require the currents and the forces of biochemical reaction networks to be always aligned.

[1] A. Wachtel, R. Rao and M. Esposito, arXiv:1709.06045 (2017)