Electrostatic interactions in concentrated protein solutions

Shradha Mishra; Jeremy D. Schmit

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arXiv · 1304.2481

Electrostatic interactions in concentrated protein solutions

Shradha Mishra·Jeremy D. Schmit

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Abstract

We present an approximate method for calculating the electrostatic free energy of concentrated protein solutions. Our method uses a cell model and accounts for both the coulomb energy and the entropic cost of Donnan salt partitioning. The former term is calculated by linearizing the Poisson-Boltzmann equation around a nonzero average potential, while the second term is calculated using a jellium approximation that is empirically modified to reproduce the dilute solution limit. When combined with a short-ranged binding interaction, calculated using the mean spherical approximation, our model reproduces osmotic pressure measurements of bovine serum albumin solutions. We also use our free energy to calculate the salt-dependent shift in the critical temperature of lysozyme solutions and show why the predicted salt partitioning between the dilute and dense phases has proven experimentally elusive.

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Shradha Mishra, Jeremy D. Schmit. 2013-04-09. Electrostatic interactions in concentrated protein solutions. https://arxiv.org/abs/1304.2481

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