-transparent.png){kind=logo}
Aqueous dispersions of monovalent and divalent cations salts of O-(1,2-dipalmitosyl-sn-glycero-3-phosphoryl)cholesterol form multilamellar vesicles as shown by freeze-fracture electron microscopy, by electron micrographs of the negatively stained liposomes, and by swelling curves of liposomes in hypo-osmotic medium. Differential scanning calorimetry reveals that aqueous dispersions of divalent metal salts of O-(1,2-dipalmitoyl-sn-glycero-3-phosphoryl)cholesterol undergo a characteristic thermotropic phase transition with a relatively large cooperative unit (n greater than 250 for the calcium salt). In contrast, monovalent cation salts of O-(1,2-dipalmitoyl-sn-glycero-3-phosphoryl)cholesterol do not show a thermotropic phase transition under comparable conditions. The molecular area of 0-(1,2-dipalmitoyl-sn-glycero-3-phosphoryl)cholesterol in a monolayer is the same in the presence and absence of Ca2+, and is virtually equal to the area of an equimolar mixture of dipalmitoyl phosphatidic acid and cholesterol. To account for the novel state induced by Ca2+, on aqueous dispersions of O-(1,2-dipalmitoyl-sn-glycero-3-phosphoryl)cholesterol (i.e., bilayer organization and highly cooperative phase transition), a linear array model is proposed in which Ca2+ bridges adjacent arrays of O-(1,2-dipalmitoyl-sn-glycero-3-phosphoryl)cholesterol molecules, thus freezing the acyl chains in their normal state. One of the main corollaries of the model is that the cooperative unit for a thermotropic phase transition is essentially one-dimensional, rather than a two-dimensional matrix. O-(1,2-Dipalmitoyl-sn-glycero-3-phosphoryl)cholesterol is proposed as an orientationally and conformationally restricted analog of glycerophospholipid plus cholesterol in bilayers.
M K Jain, and
F Ramirez, and
T M McCaffrey, and
P V Ioannou, and
J F Marecek, and
J Leunissen-Bijvelt
July 1978,
Biochimica et biophysica acta,
M K Jain, and
F Ramirez, and
T M McCaffrey, and
P V Ioannou, and
J F Marecek, and
J Leunissen-Bijvelt
April 1992,
Journal of chromatography,
M K Jain, and
F Ramirez, and
T M McCaffrey, and
P V Ioannou, and
J F Marecek, and
J Leunissen-Bijvelt
September 1987,
Lipids,
M K Jain, and
F Ramirez, and
T M McCaffrey, and
P V Ioannou, and
J F Marecek, and
J Leunissen-Bijvelt
October 2002,
Biophysical journal,
M K Jain, and
F Ramirez, and
T M McCaffrey, and
P V Ioannou, and
J F Marecek, and
J Leunissen-Bijvelt
May 1998,
Journal of biochemistry,
M K Jain, and
F Ramirez, and
T M McCaffrey, and
P V Ioannou, and
J F Marecek, and
J Leunissen-Bijvelt
January 1988,
European biophysics journal : EBJ,
M K Jain, and
F Ramirez, and
T M McCaffrey, and
P V Ioannou, and
J F Marecek, and
J Leunissen-Bijvelt
October 2022,
Applied spectroscopy,
M K Jain, and
F Ramirez, and
T M McCaffrey, and
P V Ioannou, and
J F Marecek, and
J Leunissen-Bijvelt
May 1981,
Proceedings of the National Academy of Sciences of the United States of America,
M K Jain, and
F Ramirez, and
T M McCaffrey, and
P V Ioannou, and
J F Marecek, and
J Leunissen-Bijvelt
September 1978,
Lipids,
M K Jain, and
F Ramirez, and
T M McCaffrey, and
P V Ioannou, and
J F Marecek, and
J Leunissen-Bijvelt
December 2007,
Biochimica et biophysica acta,
