Mean-field and Monte Carlo simulation studies of the lateral distribution of proteins in membranes

Maria M. Sperotto, Ole G. Mouritsen

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42 Citations (Scopus)

Abstract

Monte Carlo simulations and mean-field calculations have been applied to a statistical mechanical lattice model of lipid-protein interactions in membranes in order to investigate the phase equilibria as well as the state of aggregation of small integral membrane proteins in dipalmitoyl phosphatidylcholine bilayers. The model, which provides a detailed description of the pure lipid bilayer phase transition, incorporates hydrophobic matching between the lipid and protein hydrophobic thicknesses as a major contribution to the lipid-protein interactions. The model is analyzed in the regime of low protein concentration. It is found that a large mismatch between the lipid and protein hydrophobic thicknesses does not guarantee protein aggregation even though it strongly affects the phase behaviour. This result is consistent with experimental work (Lewis and Engelman 1983) considering the effect of lipid acyl-chain length on the planar organization of bacteriorhodopsin in fluid phospholipid bilayers. The model calculations predict that the lipid-mediated formation of protein aggregates in the membrane plane is mainly controlled by the strength of the direct lipid-protein hydrophobic attractive interaction but that direct protein-protein interactions are needed to induce substantial aggregation.

Original languageEnglish
JournalEuropean Biophysics Journal
Volume19
Issue number4
Pages (from-to)157-168
Number of pages12
ISSN0175-7571
DOIs
Publication statusPublished - 1991
Externally publishedYes

Keywords

  • Hydropobic thickness
  • Lipid bilayer
  • Lipid-protein interactions
  • Mean-field theory
  • Monte Carlo simulation
  • Phase transition
  • Protein aggregation

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