Grimaldo, M, Lopez, H, Beck, C, Roosen-Runge, F, Moulin, M, Devos, JM, Laux, V, Härtlein, M, Da Vela, S, Schweins, R, Mariani, A, Zhang, F, Barrat, J-L, Oettel, M, Forsyth, VT, Seydel, T and Schreiber, F (2019) Protein Short-Time Diffusion in a Naturally Crowded Environment. Journal of Physical Chemistry Letters, 10 (8). 1709 - 1715. ISSN 1948-7185

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The interior of living cells is a dense and polydisperse suspension of macromolecules. Such a complex system challenges an understanding in terms of colloidal suspensions. As a fundamental test we employ neutron spectroscopy to measure the diffusion of tracer proteins (immunoglobulins) in a cell-like environment (cell lysate) with explicit control over crowding conditions. In combination with Stokesian dynamics simulation, we address protein diffusion on nanosecond time scales where hydrodynamic interactions dominate over negligible protein collisions. We successfully link the experimental results on these complex, flexible molecules with coarse-grained simulations providing a consistent understanding by colloid theories. Both experiments and simulations show that tracers in polydisperse solutions close to the effective particle radius Reff = ⟨ Ri3⟩1/3 diffuse approximately as if the suspension was monodisperse. The simulations further show that macromolecules of sizes R > Reff ( R < Reff) are slowed more (less) effectively even at nanosecond time scales, which is highly relevant for a quantitative understanding of cellular processes.

Item Type: Article
Additional Information: This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.
Subjects: Q Science > Q Science (General)
Q Science > QH Natural history
Divisions: Faculty of Natural Sciences > School of Life Sciences
Related URLs:
Depositing User: Symplectic
Date Deposited: 16 May 2019 10:31
Last Modified: 16 May 2019 10:31

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