Lipid-protein interactions in lipovitellin
Lipid-protein interactions in lipovitellin
复制标题
DOI：
10.1021/bi025674w
复制
发表时间：
2002-07-30
期刊：
影响因子：
2.9
通讯作者：
Banaszak, LJ
中科院分区：
文献类型：
--
作者：
Thompson, JR;Banaszak, LJ
改进的卵黄脂磷蛋白的分子结构描述使用同步辐射冷冻电子照相术数据到1.9埃的分辨率。卵黄脂磷蛋白是在产蛋动物的蛋黄中发现的主要脂蛋白，并且参与脂质和金属的储存。认为其氨基酸序列与载脂蛋白B和负责低密度脂蛋白组装的微粒体转移蛋白片段相关。卵黄脂磷蛋白含有约16%（w/w）非共价结合的脂质（主要是磷脂）的异质混合物。先前在环境温度下的X射线结构研究描述了几种不同的蛋白质结构域，包括二聚体蛋白质的每个亚基中的大空腔。在室温下，该空腔没有脂质分子的任何可见电子密度，表明与蛋白质仅存在动态相互作用。在100 K下，该晶体学研究的一个重要结果是沿着结合腔的壁沿着出现了一些结合有序的脂质。由于电子密度的不连续性，很难精确识别脂质类型。然而，已发现7种磷脂和43种长度大于5个原子的烃链段的构象。结合脂质的构象和蛋白质和脂质之间的相互作用提供了对脂蛋白形成的因素的见解。
The refined molecular structure of lipovitellin is described using synchrotron cryocrystallographic data to 1.9 Angstrom resolution. Lipovitellin is the predominant lipoprotein found in the yolk of egglaying animals and is involved in lipid and metal storage. It is thought to be related in amino acid sequence to segments of apolipoprotein B and the microsomal transfer protein responsible for the assembly of low-density lipoproteins. Lipovitellin contains a heterogeneous mixture of about 16% (w/w) noncovalently bound lipid, mostly phospholipid. Previous X-ray structural studies at ambient temperature described several different protein domains including a large cavity in each subunit of the dimeric protein. The cavity was free of any visible electron density for lipid molecules at room temperature, suggesting that only dynamic interactions exist with the protein. An important result from this crystallographic study at 100 K is the appearance of some bound ordered lipid along the walls of the binding cavity. The precise identification of the lipid type is difficult because of discontinuities in the electron density. Nonetheless, the conformations of 7 phospholipids and 43 segments of hydrocarbon chains greater than 5 atoms in length have been discovered. The conformations of the bound lipid and the interactions between protein and lipid provide insights into the factors governing lipoprotein formation.