Non-monotonic variation with salt concentration of the second virial coefficient in protein solutions

Abstract

The osmotic virial coefficient $B_2$ of globular protein solutions is calculated as a function of added salt concentration at fixed pH by computer simulations of the ``primitive model''. The salt and counter-ions as well as a discrete charge pattern on the protein surface are explicitly incorporated. For parameters roughly corresponding to lysozyme, we find that $B_2$ first decreases with added salt concentration up to a threshold concentration, then increases to a maximum, and then decreases again upon further raising the ionic strength. Our studies demonstrate that the existence of a discrete charge pattern on the protein surface profoundly influences the effective interactions and that non-linear Poisson Boltzmann and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory fail for large ionic strength. The observed non-monotonicity of $B_2$ is compared to experiments. Implications for protein crystallization are discussed.

43 pages, including 17 figures

References in corpus (4)

• Effective forces in colloidal mixtures: from depletion attraction to accumulation repulsion
• Effective potentials for polymers and colloids: Beyond the van der Waals picture of fluids?
• Discrete charge patterns, Coulomb correlations and interactions in protein solutions
• Spherical Colloids: Effect of Discrete Macroion Charge Distribution and Counterion Valence

Cited by in corpus (9)

• A simple patchy colloid model for the phase behavior of lysozyme dispersions
• Modeling Equilibrium Clusters in Lysozyme Solutions
• Attraction between DNA molecules mediated by multivalent ions
• Extended law of corresponding states for protein solutions
• Controlled DNA compaction within chromatin: the tail-bridging effect
• Coupling between bulk- and surface chemistry in suspensions of charged colloids
• DDFT calibration and investigation of an anisotropic phase-field crystal model
• The renormalized Jellium model of colloidal suspensions with multivalent counterions
• Extracting short-ranged interactions from structure factors