Determination of specific and non-specific protein–protein interactions for beta-lactoglobulin by analytical ultracentrifugation and membrane osmometry experiments

Abstract

Protein-protein interactions are essential for the understanding of biological processes. Specific protein aggregation is an important aspect for many biological systems. In particular, electrostatic interactions play the key role for...

Accurate calculation of second osmotic virial coefficients of proteins using mixed Poisson–Boltzmann and extended DLVO theory

“…PMF was calculated by summing interactions between the corresponding bead pairs from each protein pair, according to eqn (4)- (12). The PMF and B 22 were calculated by the inhouse code, and B 22 was determined by numerical integration of the PMF over different protein-protein orientations according to eqn (2).…”

“…The second osmotic virial coefficient, B 22 , serves as a valuable indicator of the overall interactions between two macromolecules in a solution, 11 as well as a measure of weak, nonspecific interactions. 12 The B 22 coefficient is defined by the deviation of the solution from ideal behaviour and quantifies the extent to which the osmotic pressure differs from that of an ideal solution:…”

“…Here, solubility of macromolecules or particles can be modelled using either the thermodynamic relationship between solubility and second osmotic virial coefficients, 14,18 or through semiempirical models, in which adjustable parameters are fitted from experimental data. 15,16 Various experimental techniques can be used to measure second osmotic virial coefficients, including membrane osmometry, 12,23 self interaction chromatography, 7 dynamic or static light scattering, [24][25][26][27] sedimentation equilibrium, and small angle X-ray or neutron scattering (SAXS/SANS). 28,29 However, these techniques have limitations, as they can be time-consuming or require large amounts of protein samples, making them unsuitable for quick screening of PPIs under various solution conditions.…”

“…The second osmotic virial coefficient, B 22 , serves as a valuable indicator of the overall interactions between two macromolecules in a solution, 11 as well as a measure of weak, nonspecific interactions. 12 The B 22 coefficient is defined by the deviation of the solution from ideal behaviour and quantifies the extent to which the osmotic pressure differs from that of an ideal solution:where Π is the osmotic pressure, c p is the protein concentration (in mass units), R is the gas constant, T is the temperature in K and M w is the molecular weight of the protein. Positive values of the coefficient indicate overall repulsive interactions between proteins in solution, while negative values indicate attractive interactions.…”

“…Various experimental techniques can be used to measure second osmotic virial coefficients, including membrane osmometry, 12,23 self interaction chromatography, 7 dynamic or static light scattering, 24–27 sedimentation equilibrium, and small angle X-ray or neutron scattering (SAXS/SANS). 28,29 However, these techniques have limitations, as they can be time-consuming or require large amounts of protein samples, making them unsuitable for quick screening of PPIs under various solution conditions.…”