[Supermolecular organization of apolipoprotein E in solution].
The aggregation behaviour and stability in solution of apolipoprotein E (apoE) isolated from human blood plasma very low density lipoproteins were investigated. The equilibrium denaturation of fluorescein-labeled apoE by guanidine-hydrochloride determined by anisotropy and overall intensity of fluorescence, shift of the emission spectrum maximum and gel-chromatographic behaviour was characterized by reversibility, biphasity, apoE concentration dependence and the existence of native structure of the apoE monomer. The contribution of the long-living component to the kinetic dependence of fluorescence anisotropy in the presence of the 6 M denaturant increased with an increase in apoE concentration. The data obtained fit into the following scheme: oligomer (upon aging of the preparation) in equilibrium tetramer in equilibrium native monomer in equilibrium denaturated monomer. The presence in the tetrameric structure of apoE of two domains is postulated; one of those is formed by lipid-binding fragments during aggregation of individual molecules of apoE. Monoclonal antibody 3D12F11 (subclass IgG1) showed a high affinity for the apoE (Kd = 3.5 +/- 0.5 nM) without any effect on the apoprotein binding to heparin-Sepharose and apoE-induced destruction of dipalmitoylphosphatidylcholine liposomes. It is concluded that the 3D12F11 epitope is localized outside heparin- and lipid-binding sites of the apoprotein molecule.
Dergunov
A D
AD
Shuvaev
V V
VV
Ianushevskaia
E V
EV
D000911:Antibodies, Monoclonal; D001057:Apolipoproteins E / Q000737:chemistry*; D000939:Epitopes / Q000276:immunology; D005454:Fluorescence Polarization; D006801:Humans; D011487:Protein Conformation; D011489:Protein Denaturation; D012996:Solutions
D000911:Antibodies, Monoclonal; D001057:Apolipoproteins E; D000939:Epitopes; D012996:Solutions
Nadmolekuliarnaia organizatsiia apolipoproteina E v rastvore.