A model-free method for extracting interaction potential between protein molecules using small-angle X-ray scattering

Tomonari Sumi, Hiroshi Imamura, Takeshi Morita, Keiko Nishikawa

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


A small-angle X-ray scattering has been used to probe protein-protein interaction in solution. Conventional methods need to input modeled potentials with variable/invariable parameters to reproduce the experimental structure factor. In the present study, a model-free method for extracting the excess part of effective interaction potential between proteinmolecules in solutions over an introduced hard-sphere potential by using experimental data of small-angle X-ray scattering is presented on the basis of liquid-state integral equation theory. The reliability of the model-free method is tested by the application to experimentally derived structure factors for dense lysozyme solutions with different solution conditions [Javid et al., Phys. Rev. Lett. 99, 028101 (2007), Schroer et al., Phys. Rev. Lett. 106, 178102 (2011)]. The structure factors calculated from themodel-free method agree well with the experimental ones. The model-free method provides the following picture of the lysozyme solution: these are the stabilization of contact-pair configurations, large activation barrier against their formations, and screened Coulomb repulsion between the charged proteins. In addition, the model-free method will be useful to verify whether or not a model for colloidal system is acceptable to describing protein-protein interaction.

Original languageEnglish
Pages (from-to)42-46
Number of pages5
JournalJournal of Molecular Liquids
Issue numberPA
Publication statusPublished - Dec 2014


  • DLVO model
  • Integral equation
  • Liquid state theory
  • Lysozyme
  • Protein solutions
  • Protein-protein interaction

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry
  • Materials Chemistry


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