TY - JOUR
T1 - Human very low density lipoprotein structure
T2 - Interaction of the C apolipoproteins with apolipoprotein B-100
AU - Yang, C. Y.
AU - Gu, Z. W.
AU - Valentinova, N.
AU - Pownall, H. J.
AU - Lee, B.
AU - Yang, M.
AU - Xie -, Y. H.
AU - Guyton, J. R.
AU - Vlasik, T. N.
AU - Fruchart, J. C.
AU - Gotto, A. M.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1993
Y1 - 1993
N2 - Very low density lipoproteins (VLDL) are a heterogenous population of particles differing in size and composition. Heparin-Sepharose chromatography yields three VLDL subfractions. Two subfractions, VLDL(NR-1) and VLDL(NR-2), which are not retained by heparin, contain little or no detectable apolipoprotein (apo)E. According to negative stain electron microscopy, VLDL(NR-1) is slightly larger than VLDL(NR-2). The third fraction, VLDL(R), is composed of smaller particles that are retained by the heparin-Sepharose and contain apoE. The C apolipoproteins of the respective VLDL subfractions transfer to 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) single bilayer vesicles giving three subfractions designated VLDL(NR-1)-C, VLDL(NR-2)-C, and VLDL(R)-C. The protein, phospholipid, and cholesterol (free + esterified) contents decrease in the order VLDL(R)>VLDL(NR-2)>VLDL(NR-1). Triglyceride content decreases in the opposite order. POPC treatment of each VLDL subfraction increases the phospholipid and decreases the protein, triglyceride, and cholesteryl ester contents, while free cholesterol remains unchanged. According to immunological analysis of each subfraction with well- characterized monoclonal antibodies, the accessibility of some epitopes of apoB-100 on VLDL is changed by POPC treatment. Electron-microscopic analysis of POPC-treated VLDL subfraction reveals vacancies on the surfaces of each particle. VLDL(NR-1), VLDL(NR-2), and VLDL(R) are resistant to thrombin cleavage, whereas the lipoproteins lacking C apolipoproteins are not. Thrombin cleavage (8 h) of apoB-100 of VLDL(NR-2)-C and VLDL(R)-C gives two fragments, T1 and T2, that are converted to smaller fragments only after prolonged treatment. In contrast, apoB-100 of VLDL(NR-1)-C is converted into small fragments after 8 h thrombin treatment. These results suggest that removal of apoCs affects the accessibility and conformation of apoB-100 in the individual VLDL subfractions in the region near residue 3249, which is the primary thrombin cleavage site and the epitope of monoclonal antibody 4C11.
AB - Very low density lipoproteins (VLDL) are a heterogenous population of particles differing in size and composition. Heparin-Sepharose chromatography yields three VLDL subfractions. Two subfractions, VLDL(NR-1) and VLDL(NR-2), which are not retained by heparin, contain little or no detectable apolipoprotein (apo)E. According to negative stain electron microscopy, VLDL(NR-1) is slightly larger than VLDL(NR-2). The third fraction, VLDL(R), is composed of smaller particles that are retained by the heparin-Sepharose and contain apoE. The C apolipoproteins of the respective VLDL subfractions transfer to 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) single bilayer vesicles giving three subfractions designated VLDL(NR-1)-C, VLDL(NR-2)-C, and VLDL(R)-C. The protein, phospholipid, and cholesterol (free + esterified) contents decrease in the order VLDL(R)>VLDL(NR-2)>VLDL(NR-1). Triglyceride content decreases in the opposite order. POPC treatment of each VLDL subfraction increases the phospholipid and decreases the protein, triglyceride, and cholesteryl ester contents, while free cholesterol remains unchanged. According to immunological analysis of each subfraction with well- characterized monoclonal antibodies, the accessibility of some epitopes of apoB-100 on VLDL is changed by POPC treatment. Electron-microscopic analysis of POPC-treated VLDL subfraction reveals vacancies on the surfaces of each particle. VLDL(NR-1), VLDL(NR-2), and VLDL(R) are resistant to thrombin cleavage, whereas the lipoproteins lacking C apolipoproteins are not. Thrombin cleavage (8 h) of apoB-100 of VLDL(NR-2)-C and VLDL(R)-C gives two fragments, T1 and T2, that are converted to smaller fragments only after prolonged treatment. In contrast, apoB-100 of VLDL(NR-1)-C is converted into small fragments after 8 h thrombin treatment. These results suggest that removal of apoCs affects the accessibility and conformation of apoB-100 in the individual VLDL subfractions in the region near residue 3249, which is the primary thrombin cleavage site and the epitope of monoclonal antibody 4C11.
KW - 1-palmitoyl- 2-olcoyl-phosphatidylcholine
KW - conformation of apoB-100
KW - thrombic cleavage
KW - VLDL subfraction
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M3 - Article
C2 - 8409765
AN - SCOPUS:0027327204
SN - 0022-2275
VL - 34
SP - 1311
EP - 1321
JO - Journal of lipid research
JF - Journal of lipid research
IS - 8
ER -