Protein self-diffusion in crowded solutions

Research output: Contribution to journalArticle

Abstract

Macromolecular crowding in biological media is an essential factor for cellular function. The interplay of intermolecular interactions at multiple time and length scales governs a fine-tuned system of reaction and transport processes, including particularly protein diffusion as a limiting or driving factor. Using quasielastic neutron backscattering, we probe the protein self-diffusion in crowded aqueous solutions of bovine serum albumin on nanosecond time and nanometer length scales employing the same protein as crowding agent. The measured diffusion coefficient D(φ) strongly decreases with increasing protein volume fraction χ explored within 7% ≤ φ ≤ 30%. With an ellipsoidal protein model and an analytical framework involving colloid diffusion theory, we separate the rotational D r (φ) and translational D t(φ) contributions to D(φ). The resulting D t(φ) is described by short-time self-diffusion of effective spheres. Protein self-diffusion at biological volume fractions is found to be slowed down to 20% of the dilute limit solely due to hydrodynamic interactions.

Details

Authors
  • Felix Roosen-Runge
  • Marcus Hennig
  • Fajun Zhang
  • Robert M J Jacobs
  • Michael Sztucki
  • Helmut Schober
  • Tilo Seydel
  • Frank Schreiber
External organisations
  • University of Tübingen
  • Institut Laue Langevin
  • University of Oxford
  • European Synchrotron Radiation Facility
Research areas and keywords

Keywords

  • Globular proteins, Macromolecular crowding, Quasi-elastic neutron scattering
Original languageEnglish
Pages (from-to)11815-11820
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number29
Publication statusPublished - 2011 Jul 19
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes