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标题：Conformation of apolipoprotein B after lipid extraction of low density lipoproteins attached to an electron microscope grid.
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作者：M L Phillips ; V N Schumaker
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：1989
卷号：30
期号：3
页码：415-422
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：We have examined the shape of apolipoprotein B (apoB) from low density lipoproteins (LDL) using a new method to prepare the electron microscope grids. After adsorption of the lipoproteins to a carbon-coated copper grid, lipids were extracted with ethanol-ether 4:1; an aqueous negative stain was then applied. When the LDL residue was examined after this treatment, apoB, together with residual lipid, appeared as an elongated flexible structure about 600-700 A in length consisting of multiple domains of variable width from 20-70 A. Occasionally, the elongated apoB formed an irregular ring-shaped structure, but most of the rings were open. When LDL were pretreated with glutaraldehyde, then adsorbed, extracted, and stained, most of the images were closed rings with an average contour length of 700 A, again consisting of multiple domains of variable sizes. These results are consistent with apoB being composed of multiple domains arranged in an elongated structure on the surface of the LDL, and with distant domains possessing a mutual affinity that favors their cross-linking.