Soulages J L, Brenner R R
Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CONICET-UNLP, Facultad de Ciencias Médicas, La Plata, Argentina.
J Lipid Res. 1991 Mar;32(3):407-15.
High density lipophorin (HDLp is the main lipoprotein found in resting insect hemolymph. It has, in general, two molecules of apolipoproteins: apoLp-I (250 kDa) and apoLp-II (80 kDa) and a variable lipid content which ranges from 35% to 59% (w/w). Diacylglycerols (DG), phospholipids (PL), and hydrocarbons (HC) are the main lipid components, whereas cholesterol and triacylglycerols are minor components. DG content varies from 7 to 30%, PL from 11 to 24%, and HC from 0 to 15%. In order to determine the relationship between the lipid composition and the arrangement of lipid and protein components in the lipoprotein particle, a density-composition structural model was designed. The model was established by means of 12 sets of data on lipophorin density-composition relationships, and model validity was determined throughout lipoprotein space- and surface-filling conditions. Despite the differences among the lipid compositions of lipophorins, it is concluded that there are several unifying structural restrictions that govern the molecular organization of lipophorins. Quantitative treatment of the model indicates that lipophorin structure is consistent with the following. 1) Spherical particles with a protein-rich outer layer of approximately 20-21 A thickness, comprised of proteins, phospholipids, cholesterol, and small amounts of DG, and a lipid-rich core composed of HC, TG, and almost all the lipophorin DG. 2) Apolipophorins have a lipid-embedded localization within the lipoprotein particle. They might represent one of the few examples of proteins containing beta-shift structure, exerting strong hydrophobic interaction and having a lipid-embedded localization.(ABSTRACT TRUNCATED AT 250 WORDS)
高密度脂蛋白（HDLp）是静息昆虫血淋巴中发现的主要脂蛋白。一般来说，它有两个载脂蛋白分子：载脂蛋白Lp-I（250 kDa）和载脂蛋白Lp-II（80 kDa），以及可变的脂质含量，范围为35%至59%（重量/重量）。二酰基甘油（DG）、磷脂（PL）和烃类（HC）是主要的脂质成分，而胆固醇和三酰甘油是次要成分。DG含量从7%到30%不等，PL从11%到24%不等，HC从0%到15%不等。为了确定脂质组成与脂蛋白颗粒中脂质和蛋白质成分排列之间的关系，设计了一个密度-组成结构模型。该模型是通过12组关于脂蛋白密度-组成关系的数据建立的，并在整个脂蛋白空间和表面填充条件下确定了模型的有效性。尽管脂蛋白的脂质组成存在差异，但得出的结论是，有几个统一的结构限制支配着脂蛋白的分子组织。对该模型的定量处理表明，脂蛋白结构符合以下情况。1） 球形颗粒，其富含蛋白质的外层厚度约为20-21埃，由蛋白质、磷脂、胆固醇和少量DG组成，脂质丰富的核心由HC、TG和几乎所有脂蛋白DG组成。2） 载脂蛋白在脂蛋白颗粒内有脂质嵌入定位。它们可能是少数含有β-位移结构、具有强疏水相互作用且有脂质嵌入定位的蛋白质实例之一。（摘要截断于250字）
