Anomalous Protein-Protein Interactions in Multivalent Salt Solution

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Abstract

The stability of aqueous protein solutions is strongly affected by multivalent ions, which induce ion-ion correlations beyond the scope of classical mean-field theory. Using all-atom molecular dynamics (MD) and coarse grained Monte Carlo (MC) simulations, we investigate the interaction between a pair of protein molecules in 3:1 electrolyte solution. In agreement with available experimental findings of "reentrant protein condensation", we observe an anomalous trend in the protein-protein potential of mean force with increasing electrolyte concentration in the order: (i) double-layer repulsion, (ii) ion-ion correlation attraction, (iii) overcharge repulsion, and in excess of 1:1 salt, (iv) non Coulombic attraction. To efficiently sample configurational space we explore hybrid continuum solvent models, applicable to many-protein systems, where weakly coupled ions are treated implicitly, while strongly coupled ones are treated explicitly. Good agreement is found with the primitive model of electrolytes, as well as with atomic models of protein and solvent.

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Authors
Organisations
External organisations
  • Ruder Boskovic Institute
  • Institute of Organic Chemistry and Biochemistry of the Academy of Sciences of the Czech Republic
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Chemistry
Original languageEnglish
Pages (from-to)3000-3006
Number of pages7
JournalJournal of Physical Chemistry B
Volume121
Issue number14
Publication statusPublished - 2017 Apr 13
Publication categoryResearch
Peer-reviewedYes

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