title: Theory of raft formation by the cross-linking of saturated or unsaturated lipids in model lipid bilayers.
abstract: We consider the effect of cross-linking a small fraction of lipids, either saturated or unsaturated, in a mixture of saturated and unsaturated lipids and cholesterol. The change in phase behavior is examined utilizing a recent phenomenological model of the ternary system, which is extended to include a fourth component representing the cross-linked lipids. These lipids are taken to be identical to monomeric ones except for their reduced entropy of mixing. We find that even a relatively small amount of cross-linked lipids, less than 5 mol %, is sufficient to significantly expand the range of compositions within which there is coexistence between liquid-ordered and liquid-disordered phases. Equivalently, the cross-linking of lipids increases the liquid-liquid miscibility transition temperature, and therefore could bring about phase separation at a temperature at which, before cross-linking, there was only a single liquid phase.
authors.affiliation: Department of Physics, University of Washington, Seattle, Washington, USA.
authors.forename: G Garbès
authors.initials: GG
authors.lastname: Putzel
authors.forename: M
authors.initials: M
authors.lastname: Schick
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D021962:Membrane Microdomains / Q000737:chemistry*; D008954:Models, Biological
chemical_list: D003432:Cross-Linking Reagents; D008051:Lipid Bilayers