Membrane-Protein Interactions in a Generic Coarse-Grained Model for Lipid Bilayers

• Published in: Biophysical journal Vol. 96; no. 1; pp. 101 - 115
• Main Authors: West, Beate, Brown, Frank L.H., Schmid, Friederike
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2009; Biophysical Society; The Biophysical Society
• Subjects: Algorithms; Computer Simulation; Elastic deformation; Elasticity; Fourier Analysis; Hydrophobic and Hydrophilic Interactions; Inclusion Bodies - chemistry; Inclusion Bodies - metabolism; Lipid Bilayers - chemistry; Lipid Bilayers - metabolism; Lipids; Mathematical analysis; Mathematical models; Membrane; Membranes; Models, Chemical; Monte Carlo Method; Monte Carlo methods; Monte Carlo simulation; Proteins; Proteins - chemistry; Proteins - metabolism; RNA-protein interactions; Spectra; Surface Tension
• ISSN: 0006-3495; 1542-0086
• DOI: 10.1529/biophysj.108.138677

We study membrane-protein interactions and membrane-mediated protein-protein interactions by Monte Carlo simulations of a generic coarse-grained model for lipid bilayers with cylindrical hydrophobic inclusions. The strength of the hydrophobic force and the hydrophobic thickness of the proteins are systematically varied. The results are compared with analytical predictions of two popular analytical theories: The Landau-de Gennes theory and the elastic theory. The elastic theory provides an excellent description of the fluctuation spectra of pure membranes and successfully reproduces the deformation profiles of membranes around single proteins. However, its prediction for the potential of mean force between proteins is not compatible with the simulation data for large distances. The simulations show that the lipid-mediated interactions are governed by five competing factors: direct interactions; lipid-induced depletion interactions; lipid bridging; lipid packing; and a smooth long-range contribution. The mechanisms leading to hydrophobic mismatch interactions are critically analyzed.