Membrane properties of binary and ternary systems of ganglioside GM1/dipalmitoylphosphatidylcholine/dioleoylphosphatidylcholine.
The membrane properties of the ganglioside GM1 (GM1)/dioleoylphosphatidylcholine (DOPC) binary system and GM1/dipalmitoylphosphatidylcholine (DPPC)/DOPC ternary system were investigated using surface pressure measurements and atomic force microscopy (AFM), and the effect of surface pressure on the properties of the membranes was examined. Mixed GM1/DPPC/DOPC monolayers were deposited on mica using the Langmuir-Blodgett technique for AFM. GM1 and DOPC were immiscible and phase-separated. The AFM image of the GM1/DOPC (1:1) monolayer showed island-like GM1 domains embedded in the DOPC matrix. There was no morphological change on varying surface pressure. The surface pressure-area isotherm of the GM1/DPPC/DOPC (2:9:9) monolayer showed a two-step collapse as in the DPPC/DOPC (1:1) monolayer. The AFM image for the GM1/DPPC/DOPC monolayer showed DPPC and GM1 domains in the DOPC matrix, and the DPPC-rich phase containing GM1 showed a percolation pattern the same as the GM1/DPPC (1:9) monolayer. The percolation pattern in the GM1/DPPC/DOPC monolayer changed as the surface pressure was varied. The surface pressure-responsive change in morphology of GM1 was affected by the surrounding environment, suggesting that the GM1 localized in each organ has a specific role.
Ohta
Yumiko
Y
Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
Yokoyama
Shoko
S
Sakai
Hideki
H
Abe
Masahiko
M
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D005677:G(M1) Ganglioside / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D010713:Phosphatidylcholines / Q000737:chemistry*; D011312:Pressure; D013499:Surface Properties; D013696:Temperature
D010713:Phosphatidylcholines; D015060:1,2-Dipalmitoylphosphatidylcholine; D005677:G(M1) Ganglioside; C017251:1,2-oleoylphosphatidylcholine