Optimized Baxter Model of Protein Solutions: Electrostatics versus Adhesion

Abstract

A theory is set up of spherical proteins interacting by screened electrostatics and constant adhesion, in which the effective adhesion parameter is optimized by a variational principle for the free energy. An analytical approach to the second virial coefficient is first outlined by balancing the repulsive electrostatics against part of the bare adhesion. A theory similar in spirit is developed at nonzero concentrations by assuming an appropriate Baxter model as the reference state. The first-order term in a functional expansion of the free energy is set equal to zero which determines the effective adhesion as a function of salt and protein concentrations. The resulting theory is shown to have fairly good predictive power for the ionic-strength dependence of both the second virial coefficient and the osmotic pressure or compressibility of lysozyme up to about 0.2 volume fraction.

40 pages, 9 figures

References in corpus (2)

• Competition of percolation and phase separation in a fluid of adhesive hard spheres
• Measurements of Protein-Protein Interactions by Size Exclusion Chromatography

Cited by in corpus (4)

• Fluid-crystal coexistence for proteins and inorganic nanocolloids: dependence on ionic strength
• Phase behavior of weakly polydisperse sticky hard spheres: Perturbation theory for the Percus-Yevick solution
• Collective diffusion coefficient of proteins with hydrodynamic, electrostatic and adhesive interactions
• Application of the Optimized Baxter Model to the hard-core attractive Yukawa system