Diffusion of Integral Membrane Proteins in Protein-Rich Membranes

  • 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.

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Author:Matti JavanainenORCiD, Hector Martinez-Seara, Ralf MetzlerORCiD, Ilpo VattulainenORCiD
Pubmed Id:http://www.ncbi.nlm.nih.gov/pubmed?term=28823153
Parent Title (English):The journal of physical chemistry letters
Publisher:American Chemical Society
Place of publication:Washington
Document Type:Article
Year of first Publication:2017
Year of Completion:2017
Release Date:2020/04/20
First Page:4308
Last Page:4313
Funder:Academy of Finland (Centre of Excellence program) [307415]; European Research Council (Advanced Grant CROWDED-PRO-LIPIDS) [290974]; Czech Science Foundation [208/12/G016]
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie
Peer Review:Referiert