Berlin 2018 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 20: Statistical Physics of Biological Systems DY (joint session DY/BP)

BP 20.12: Vortrag

Mittwoch, 14. März 2018, 13:00–13:15, BH-N 333

Entropic Allostery of Protein Binding and ‘Allosteron’ Networks — •Alice C. von der Heydt and Tom C.B. McLeish — Dept of Physics, Durham University, Durham, DH1 3LE, UK

Proteins form an essential part of all living organisms. Effector-binding and self-assembly are vital to their biological function. Allostery, i.e., non-local signal transduction and co-operativity among distant sites of a protein, does not imply binding to cause major structural changes. Entropic allostery, instead, rests upon a subtle tuning of the amplitudes and the spectrum of thermal fluctuation modes, to enable binding co-operativity. This mechanism (Cooper and Dryden, 1984) may provide the main part of the allosteric free energy if collective, long-wavelength modes dominate the density of thermally accessible states, and thus, coarse-grained models apply. In an effort to establish a theory of entropic allostery and to elucidate the range of applications, we construct and analyse a basic toy-model unit, the ‘allosteron’, and its association into networks akin to protein complexes. An allosteron is equipped with both internal and coupling, harmonic degrees of freedom whose interaction strengths can be modified through binding of ligands. Physical interaction strengths derive from a class of Lennard-Jones potentials defined via the balance of attractive and repulsive (entropic) forces. The impact of entropic allostery is demonstrated and discussed for the binding of proteins and their assemblies, such as ring oligomers, that are suitably modelled by coupled allosterons.