A generalized free-solvent model for the osmotic pressure of multi-component solutions containing protein–protein interactions

Abstract

a b s t r a c tThe free-solvent model has been shown to have excellent predictability of the osmotic pressure for single and binary non-interactive proteins in aqueous solutions. Here the free-solvent model is extended to be more generalized by including the contributions of intra-and inter-protein interactions to the osmotic pressure of a solution in the form of homo-and hetero-multimers. The solute-solvent interactions are considered to be unique for each homo-and hetero-multimer in solution. The effect of the various generalized free-solvent model parameters on the osmotic pressure are examined for a single protein solution with a homo-dimer, a binary protein solution with no protein-protein interactions, and a binary protein solution with a hetero-dimer. Finally, the limitations associated with the generalized free-solvent model are discussed.

Interrogating the Osmotic Pressure of Self-Crowded Bovine Serum Albumin Solutions: Implications of Specific Monovalent Anion Effects Relative to the Hofmeister Series

“…However, because of the nearly unobserved ion binding, the osmotic pressures of NaI and NaSCN were over 50 kPa higher than that of NaF. We showed previously that at high self-crowded concentrations, the FSB model predicts that increase in ion binding can deaccelerate the increase in osmotic pressure with respect to increasing concentration …”

“…[46][47][48][49][50][51] However, we have shown that, via our FSB model, the bulk property, osmotic pressure, of self-crowded proteins and crowded binary globular protein solutions can directly provide ion binding and hydration properties of proteins, specifically in the highly crowded regions where the rate of change of osmotic pressure to protein concentration is highly non-linear. [52][53][54][55][56][57][58][59][60][61][62][63] Because the FSB model focuses on protein hydration and ion-binding, it can provide a fortuitous approach in interrogating anion effects on crowded protein solutions.…”

“…We showed previously that at high self-crowded concentrations, the FSB model predicts that increases in ion binding can deaccelerate the increase in osmotic pressure with respect to increasing concentration. 63…”

“…We showed previously that at high self-crowded concentrations, the FSB model predicts that increase in ion binding can deaccelerate the increase in osmotic pressure with respect to increasing concentration. 63 Hydration Changes due to Anion Effects May Correlate with SASA Changes. We have previously reported that a monolayer of water on BSA is approximately 1 g H 2 O/1 g BSA when in moderate NaCl at physiological pH.…”

“…Osmotic pressure does not give direct crystallization information. Nevertheless, a number of researchers have used osmotic pressure to address observed phenomena of proteins in ionic aqueous solutions via protein–protein interactions. − However, we have shown that via our FSB model, the bulk property, osmotic pressure of self-crowded proteins and crowded binary globular protein solutions can directly provide ion binding and hydration properties of proteins, specifically in the highly crowded regions where the rate of change of osmotic pressure to protein concentration is highly nonlinear. − Because the FSB model focuses on protein hydration and ion binding, it can provide a fortuitous approach in interrogating anion effects on crowded protein solutions.…”