Ordered nanoclusters in lipid-cholesterol membranes.
X-ray diffraction of sphingomyelin-dihydrocholesterol (SM-DChol) monolayers revealed short-ranged ( approximately 25 A) 2D ordering. These nanoclusters show two distinct regions: below the cusp point of the phase diagram (35 mol% DChol), a constant d spacing was observed; above the cusp, the d spacing increases linearly with DChol in accordance to Vegard's law for binary alloys. The components in this lipidic alloy are thus a 65ratio35 SM-DChol entity and excess DChol. Reflectivity data further support the emergence above the cusp of an uncomplexed DChol population with greater vertical mobility.
Ratajczak
Maria K
MK
Department of Physics, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, USA.
Chi
Eva Y
EY
Frey
Shelli L
SL
Cao
Kathleen D
KD
Luther
Laura M
LM
Lee
Ka Yee C
KY
Majewski
Jaroslaw
J
Kjaer
Kristian
K
D004083:Cholestanol / Q000737:chemistry*; D008560:Membrane Fluidity; D008567:Membranes, Artificial; D049329:Nanostructures / Q000737:chemistry*; D013109:Sphingomyelins / Q000737:chemistry*; D014961:X-Ray Diffraction
D008567:Membranes, Artificial; D013109:Sphingomyelins; D004083:Cholestanol