Anisotropic protein-protein interactions in dilute and concentrated solutions

Coralie Pasquier, Søren Roi Midtgaard, Marco Polimeni, Christian Isak Jørgensen, Lise Arleth, Thomas H. Callisen, Mikael Lund

Research output: Contribution to journalArticlepeer-review

Abstract

Interactions between biomolecules are ubiquitous in nature and crucial to many applications including vaccine development; environmentally friendly textile detergents; and food formulation. Using small angle X-ray scattering and structure-based molecular simulations, we explore protein–protein interactions in dilute to semi-concentrated protein solutions. We address the pertinent question, whether interaction models developed at infinite dilution can be extrapolated to concentrated regimes? Our analysis is based on measured and simulated osmotic second virial coefficients and solution structure factors at varying protein concentration and for different variants of the protein Thermomyces Lanuginosus Lipase (TLL). We show that in order to span the dilute and semi-concentrated regime, any model must carefully capture the balance between spatial and orientational correlations as the protein concentration is elevated. This requires consideration of the protein surface morphology, including possible patch interactions. Experimental data for TLL is most accurately described when assuming a patchy interaction, leading to dimer formation. Our analysis supports that the dimeric proteins predominantly exist in their open conformation where the active site is exposed, thereby maximising hydrophobic attractions that promote inter-protein alignment.

Original languageEnglish
Pages (from-to)794-804
Number of pages11
JournalJournal of Colloid and Interface Science
Volume629
DOIs
Publication statusPublished - 2023 Jan

Subject classification (UKÄ)

  • Biophysics
  • Physical Chemistry

Keywords

  • Directional interactions
  • Molecular modelling
  • Protein–protein interactions
  • Small-Angle X-ray Scattering
  • Solution stability

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