Local Lipid Reorganization by a Transmembrane Protein Domain.

Membrane proteins interact with their lipid bilayer environment via both a transmembrane helix and juxtamembrane regions. The effect of juxtamembrane regions and membrane lipid composition on these interactions has been explored by multiscale molecular dynamics simulations. The consequences of anionic lipids within the inner leaflet of a membrane were studied in combination with membrane spanning protein models differing in their juxtamembrane domains. The simulations reveal sensitivity of the protein-lipid interactions to membrane lipid composition and charged amino acid side chains. Basic residues on the intracellular side of the protein facilitated interactions with anionic lipids. Protein systems without basic residues do not show selectivity for anionic compared with zwitterionic lipids. This reveals the sensitivity to the composition of both the membrane and the protein system when studying membrane-embedded proteins. The results presented here illustrate how even a simple transmembrane domain is able to induce lipid reorganization in a mixed asymmetric bilayer.