Open AccessCritical points in charged membranes containing cholesterol
Author(s) -
Arun Radhakrishnan,
Harden M. McConnell
Publication year - 2002
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.212522699
Subject(s) - miscibility , critical point (mathematics) , phase diagram , monolayer , membrane , chemistry , ternary operation , phase (matter) , cholesterol , thermodynamics , organic chemistry , polymer , biochemistry , physics , mathematical analysis , mathematics , computer science , programming language
Epifluorescence microscopy is used to determine phase diagrams for lipid monolayers containing binary mixtures of cholesterol or dihydrocholesterol and dimyristoylphosphatidylserine, as well as ternary mixtures that also contain ganglioside G(M1). The phase diagrams are unusual in that they show multiple critical points: two upper miscibility critical points and one lower miscibility critical point. These critical points all are associated with the formation of condensed complexes between these lipids and cholesterol (or dihydrocholesterol). The miscibility critical pressures depend on subphase pH and ionic strength. Changes in critical pressures due to changes in subphase composition are closely related to changes in membrane electrostatic pressure and surface ionization.