脂質膜中單液態至雙液態的相變研究(2/2)

It is widely accepted that lipid domains with differing lipid/protein compositions,physical properties, and function exist in the membranes. Among them, thedomains (lipid rafts) enriched in cholesterol and sphingolipid have beenimplicated to play important roles in a wide range of biological processes.Investigation of model membranes containing ternary mixtures of unsaturatedphospholipid, saturated phospholipid, and sterol have been performed on varioussystems in order to understand the interactions governing the raft formation. Oneintriguing result is that while POPC/DPPC/cholesterol membranes display onlyone liquid phase, POPC/DPPC/ergosterol membranes display coexistence of loand ld phases for a given temperature. Here we propose to study modelmembranes POPC/DPPC/(cholesterol_1-x ergosterol_x). By replacing cholesterolwith ergosterol, we attempt to observe the evolution from one liquid to two liquidby varying the sterol composition. We will also study (POPC_1-x DOPC_x)/DPPC/cholesterol model membranes, which also exhibit one liquid (x=0) to twoliquid transition (x=1) transition. We will explore the phase behavior between x=0and x=1 region. In both cases, the temperature-composition phase diagrams willbe established.