Berlin 2018 – scientific programme
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BP: Fachverband Biologische Physik
BP 29: Statistical Physics of Biological Systems I (joint session BP/DY)
BP 29.1: Talk
Thursday, March 15, 2018, 09:30–09:45, H 2013
Thermodynamic bounds on the ultra- and infra-affinity of Hsp70 for its substrates — •Basile Nguyen1,2, David Hartich1, Paolo De Los Rios2, and Udo Seifert1 — 1II. Institut für Theoretische Physik, Universität Stuttgart, Stuttgart, Germany — 2Laboratory of Statistical Biophysics, Institute of Physics, School of Basic Science and Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
The 70 kDa heat shock protein Hsp70 has several essential functions in living systems, such as protecting cells against protein aggregation, assisting protein folding, remodeling protein complexes, and driving translocation into organelles. These functions require high affinity for nonspecific amino acid sequences that are ubiquitous in proteins. It has been recently shown that this high affinity, called ultra-affinity, depends on a process driven out of equilibrium by ATP hydrolysis. Here, we establish the thermodynamic bounds for ultra-affinity, and further show that the same reaction scheme can in principle be used both to strengthen and to weaken affinities (leading in this case to infra-affinity). We show that cofactors are essential to achieve affinity beyond the equilibrium range. Finally, we consider small GTPases which can benefit from infra-affinity to optimize intracellular signal transduction.
[1] B. Nguyen, D. Hartich, U. Seifert and P. De Los Rios (2017),
white Biophys. J. 113, 362-370