Chatterton J E, Phillips M L, Curtiss L K, Milne R W, Marcel Y L, Schumaker V N
Department of Chemistry and Biochemistry, University of California, Los Angeles 90024-1569.
J Biol Chem. 1991 Mar 25;266(9):5955-62.
Apolipoprotein B (apoB) was mapped using electron microscopy to visualize pairs of monoclonal antibodies binding to the low density lipoprotein (LDL) surface. The sites at which these monoclonals bind the apoB polypeptide sequence had already been established. The angular distances between all possible pairs of binding sites except one allowed the relative placement of six epitopes on the LDL sphere. We conclude that apoB extends over at least a hemisphere of the LDL surface since four epitopes are located in the Northern Hemisphere at sites arbitrarily designated as the North Pole, the Aleutian Islands, Bogotá, and in the Atlantic Ocean, while two are found in the Southern Hemisphere at Buenos Aires and at Madagascar. ApoB appears to possess a restricted flexibility, since these relative epitope locations show a substantial standard deviation in latitude and longitude. Mapping of additional epitopes may provide an answer to the question of whether apoB circumnavigates the LDL sphere.
利用电子显微镜对载脂蛋白B（apoB）进行定位，以可视化结合到低密度脂蛋白（LDL）表面的单克隆抗体对。这些单克隆抗体与apoB多肽序列结合的位点已经确定。除了一对位点外，所有可能的结合位点对之间的角距离使得六个表位能够在LDL球体上进行相对定位。我们得出结论，apoB至少延伸到LDL表面的一个半球，因为四个表位位于北半球，分别在任意指定为北极、阿留申群岛、波哥大以及大西洋的位置，而另外两个位于南半球的布宜诺斯艾利斯和马达加斯加。由于这些相对表位位置在纬度和经度上显示出相当大的标准差，apoB似乎具有有限的灵活性。绘制更多表位的图谱可能会回答apoB是否环绕LDL球体这一问题。
