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Photo Mikael Lund

Mikael Lund

Professor

Photo Mikael Lund

Virtual cell model for osmotic pressure calculation of charged biomolecules

Author

  • Marco Polimeni
  • Coralie Pasquier
  • Mikael Lund

Summary, in English

The osmotic pressure of dilute electrolyte solutions containing charged macro-ions as well as counterions can be computed directly from the particle distribution via the well-known cell model. Originally derived within the Poisson-Boltzmann mean-field approximation, the cell model considers a single macro-ion centered into a cell, together with counterions needed to neutralize the total cell charge, while it neglects the phenomena due to macro-ion correlations. While extensively applied in coarse-grained Monte Carlo (MC) simulations of continuum solvent systems, the cell model, in its original formulation, neglects the macro-ion shape anisotropy and details of the surface charge distribution. In this paper, by comparing one-body and two-body coarse-grained MC simulations, we first establish an upper limit for the assumption of neglecting correlations between macro-ions, and second, we validate the approximation of using a non-spherical macro-ion. Next, we extend the cell model to all-atom molecular dynamics simulations and show that protein concentration-dependent osmotic pressures can be obtained by confining counterions in a virtual, spherical subspace defining the protein number density. Finally, we show the possibility of using specific interaction parameters for the protein-ion and ion-ion interactions, enabling studies of protein concentration-dependent ion-specific effects using merely a single protein molecule.

Department/s

  • Computational Chemistry
  • eSSENCE: The e-Science Collaboration
  • LINXS - Institute of advanced Neutron and X-ray Science

Publishing year

2021-11-21

Language

English

Publication/Series

Journal of Chemical Physics

Volume

155

Issue

19

Document type

Journal article

Publisher

American Institute of Physics (AIP)

Topic

  • Theoretical Chemistry (including Computational Chemistry)

Status

Published

ISBN/ISSN/Other

  • ISSN: 0021-9606