[11p-M121-1~10] Interplay and integration of experiments and calculations in nanobiotechnology: lipid membrane and membrane proteins

[11p-M121-10] Cholesterol-induced Microdomain Formation in Bilayer Membranes Consisting of Completely Miscible Lipids

〇(M2)MELVIN WeiShern GOH¹, Ayumi Hirano-Iwata², Michio Niwano³, Ryugo Tero¹ (1.Toyohashi Univ. Tech., 2.Tohoku Univ., 3.Tohoku Fukushi Univ.)

Keywords:membrane fusion, microdomain, lipid bilayer

Recently, we reported that a lipid bilayer comprising of egg-derived phosphatidylcholine (PC), phosphatidylethanolamine (PE) and cholesterol (Chol) contains microdomains that act as specific proteoliposome fusion sites. Phase separation in Chol-containing bilayer occurs generally in partially miscible lipids such as dipalmitoyl and dioleoyl PCs. Egg-derived PC and PE are both in liquid crystalline phase, and are completely miscible at 25 ^oC without Chol. However, incorporating Chol induced microdomains formation. We investigated the mechanism of this unique microdomains formation.
We prepared PC+PE+Chol-SLBs using egg-derived and synthetic PEs. The area fraction of microdomains increased with PE concentration (C_PE), and the increment in C_PE also promoted the formation of planar SLBs from vesicles. The microdomains were in liquid-disordered-like state and PE-rich. PE with polyunsaturated chains such as the docosahexaenoyl group was the key factor of the formation of microdomains.