TY - JOUR

T1 - Mean-field and Monte Carlo simulation studies of the lateral distribution of proteins in membranes

AU - Sperotto, Maria M.

AU - Mouritsen, Ole G.

PY - 1991

Y1 - 1991

N2 - 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.

AB - 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.

KW - Hydropobic thickness

KW - Lipid bilayer

KW - Lipid-protein interactions

KW - Mean-field theory

KW - Monte Carlo simulation

KW - Phase transition

KW - Protein aggregation

U2 - 10.1007/BF00196342

DO - 10.1007/BF00196342

M3 - Journal article

C2 - 2029872

AN - SCOPUS:0025971506

VL - 19

SP - 157

EP - 168

JO - European Biophysics Journal

JF - European Biophysics Journal

SN - 0175-7571

IS - 4

ER -