Diffusion of Integral Membrane Proteins in Protein-Rich Membranes

0479162 - ÚOCHB 2018 RIV US eng J - Journal Article
Javanainen, M. - Martinez-Seara, Hector - Metzler, R. - Vattulainen, I.
Diffusion of Integral Membrane Proteins in Protein-Rich Membranes.
Journal of Physical Chemistry Letters. Roč. 8, č. 17 (2017), s. 4308-4313. ISSN 1948-7185
R&D Projects: GA ČR(CZ) GBP208/12/G016
Institutional support: RVO:61388963
Keywords : giant unilamellar vesicles * single-molecule tracking * lipid bilayer membranes
OECD category: Physical chemistry
Impact factor: 8.709, year: 2017

The lateral diffusion of embedded proteins along lipid membranes in protein-poor conditions has been successfully described in terms of the Saffman-Delbruck (SD) model, which predicts that the protein diffusion coefficient D is weakly dependent on its radius R as D proportional to ln(1/R). However, instead of being protein-poor, native cell membranes are extremely crowded with proteins. On the basis of extensive molecular simulations, we here demonstrate that protein crowding of the membrane at physiological levels leads to deviations from the SD relation and to the emergence of a stronger Stokes-like dependence D proportional to 1/R. We propose that this 1/R law mainly arises due to geometrical factors: smaller proteins are able to avoid confinement effects much better than their larger counterparts. The results highlight that the lateral dynamics in the crowded setting found in native membranes is radically different from protein-poor conditions and plays a significant role in formation of functional multiprotein complexes.
Permanent Link: http://hdl.handle.net/11104/0275160