TY - JOUR
T1 - Interaction of apoliprotein C-III with phosphatidylcholine vesicles. Dependence of aproprotein-phospholipid complex formation on vesicle structure
AU - Morrisett, Joel D.
AU - Pownall, Henry J.
AU - Gotto, Antonio
PY - 1977/1/18
Y1 - 1977/1/18
N2 - We have studied the interaction of an apolipoprotein from human very low density lipoproteins (apoC-III) with egg yolk phosphatidylcholine in the form of single- and multi-bilayer vesicles. The reactivity of single-bilayer vesicles with apoC-III1 appears to be greater than that of the multi-bilayer vesicles according to several thermodynamic and spectroscopic criteria. In the complexes formed by the association of apoC-III with single-bilayer vesicles, the α-helical content of the peptide backbone and the apolarity of the environment around the tryptophan residues are greater than that observed in the complexes formed with the multibilayer vesicles. A higher yield and more homogeneous density distribution of lipid-apoprotein complexes results from the interaction of apoC-with the single-bilayer vesicles relative to those obtained with the multibilayer vesicles. The enthalpy of association of apoC-III1 with phospholipid was greater for the single-shelled vesicles (25 kcal/mol apoC-III1) than for the multishelled ones (18 kcal/mol apoC-III1). The difference in reactivity of these two types of liposomes is not due to a difference in their fluidities since their fatty acid compositions are identical, but may be due to a difference in their areas of sterically accessible phospholipid, their permeabilities to the apoprotein, their radii of curvation, or a combination of these factors.
AB - We have studied the interaction of an apolipoprotein from human very low density lipoproteins (apoC-III) with egg yolk phosphatidylcholine in the form of single- and multi-bilayer vesicles. The reactivity of single-bilayer vesicles with apoC-III1 appears to be greater than that of the multi-bilayer vesicles according to several thermodynamic and spectroscopic criteria. In the complexes formed by the association of apoC-III with single-bilayer vesicles, the α-helical content of the peptide backbone and the apolarity of the environment around the tryptophan residues are greater than that observed in the complexes formed with the multibilayer vesicles. A higher yield and more homogeneous density distribution of lipid-apoprotein complexes results from the interaction of apoC-with the single-bilayer vesicles relative to those obtained with the multibilayer vesicles. The enthalpy of association of apoC-III1 with phospholipid was greater for the single-shelled vesicles (25 kcal/mol apoC-III1) than for the multishelled ones (18 kcal/mol apoC-III1). The difference in reactivity of these two types of liposomes is not due to a difference in their fluidities since their fatty acid compositions are identical, but may be due to a difference in their areas of sterically accessible phospholipid, their permeabilities to the apoprotein, their radii of curvation, or a combination of these factors.
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U2 - 10.1016/0005-2760(77)90067-4
DO - 10.1016/0005-2760(77)90067-4
M3 - Article
AN - SCOPUS:49449129350
VL - 486
SP - 36
EP - 46
JO - Biochimica et Biophysica Acta - Lipids and Lipid Metabolism
JF - Biochimica et Biophysica Acta - Lipids and Lipid Metabolism
SN - 0005-2760
IS - 1
ER -