Stoichiometry of lipid interactions with transmembrane proteins—Deduced from the 3D structures

摘要: The stoichiometry of the first shell lipids interacting with a transmembrane protein is defined operationally by population spin-labeled lipid chains whose motion restricted directly protein. Interaction stoichiometries have been determined experimentally for wide range α-helical integral membrane proteins using spin-label ESR spectroscopy. Here, we determine spatially number first-shell at hydrophobic perimeter 3D structure has X-ray crystallography and lipid–protein interactions characterized spin-labeling. Molecular modeling used to build single surrounding structures derived from PDB. Constrained energy optimization protein–lipid assemblies performed molecular mechanics. For relatively small (up 7–12 helices), geometrical corresponds that perturbation lipid-chain dynamics. larger, multi-subunit proteins, perturbed may either exceed or be less in than those can accommodated intramembranous perimeter. In these latter cases, motionally augmented intercalation, correspond specific subpopulation interface, respectively. monomeric β-barrel mobility 22-stranded barrel, but fewer are around an eight-stranded barrel. Deviations shell, case, smaller highly curved