2. Academic Validation
  3. Thermodynamic Bounds on the Ultra- and Infra-affinity of Hsp70 for Its Substrates

Thermodynamic Bounds on the Ultra- and Infra-affinity of Hsp70 for Its Substrates

  • Biophys J. 2017 Jul 25;113(2):362-370. doi: 10.1016/j.bpj.2017.06.010.
Basile Nguyen 1,  David Hartich 2,  Udo Seifert 2,  Paolo De Los Rios 3
Affiliations

Affiliations

  • 1 II. Institut für Theoretische Physik, Universität Stuttgart, Stuttgart, Germany; Laboratory 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. Electronic address: [email protected].
  • 2 II. Institut für Theoretische Physik, Universität Stuttgart, Stuttgart, Germany.
  • 3 Laboratory 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.
PMID: 28746847 DOI: 10.1016/j.bpj.2017.06.010
Abstract

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, biological implications are discussed.

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