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Challenges in Predicting Protein-Protein Interactions from Measurements of Molecular Diffusivity.

ABSTRACT: Dynamic light scattering can be used to measure the diffusivity of a protein within a formulation. The dependence of molecular diffusivity on protein concentration (traditionally expressed in terms of the interaction parameter k_D) is often used to infer whether protein-protein interactions are repulsive or attractive, resulting in solutions that are colloidally stable or unstable, respectively. However, a number of factors unrelated to intermolecular forces can also impact protein diffusion, complicating this interpretation. Here, we investigate the influence of multicomponent diffusion in a ternary protein-salt-water system on protein diffusion and k_D in the context of Nernst-Planck theory. This analysis demonstrates that large changes in protein diffusivity with protein concentration can result even for hard-sphere systems in the absence of protein-protein interactions. In addition, we show that dynamic light scattering measurements of diffusivity made at low ionic strength cannot be reliably used to detect protein conformational changes. We recommend comparing experimentally determined k_D values to theoretically predicted excluded-volume contributions, which will allow a more accurate assessment of protein-protein interactions.

SUBMITTER: Sorret LL

PROVIDER: S-EPMC5103004 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature

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Challenges in Predicting Protein-Protein Interactions from Measurements of Molecular Diffusivity.

Sorret Lea L LL DeWinter Madison A MA Schwartz Daniel K DK Randolph Theodore W TW

Biophysical journal 20161101 9

Dynamic light scattering can be used to measure the diffusivity of a protein within a formulation. The dependence of molecular diffusivity on protein concentration (traditionally expressed in terms of the interaction parameter k<sub>D</sub>) is often used to infer whether protein-protein interactions are repulsive or attractive, resulting in solutions that are colloidally stable or unstable, respectively. However, a number of factors unrelated to intermolecular forces can also impact protein dif ...[more]

PMID: 27806265

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Dataset Information

Challenges in Predicting Protein-Protein Interactions from Measurements of Molecular Diffusivity.

Publications

Challenges in Predicting Protein-Protein Interactions from Measurements of Molecular Diffusivity.

Similar Datasets

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