STRUCTURAL STUDIES OF LIPID/PROTEIN SYSTEMS

描述（改编自摘要）：长期目标是提供数据 脂质与转运蛋白或酶的相互作用。为了做到这一点， 含脂质大分子的分子结构将用于 描述了脂质-蛋白质相互作用。一项关于卵黄脂磷蛋白的几乎完整的研究 导致了微粒体甘油三酯转移蛋白（MTP）的类似研究， 其参与血清脂蛋白的组装。一个主要目标是 竞争MTP与蛋白质二硫化物复合物的晶体结构 异构酶对于卵黄脂磷蛋白，新的x射线测量提供了初步的 关于20个结合酰基链构象的证据。新数据将 将努力重建整个领域， 磷脂存在于卵黄脂磷蛋白中。尝试使载脂蛋白A1结晶， HDL的主要蛋白质组分将继续。 在β-氧化螺旋中，不止一种酶似乎与 每个反应。对于β-OH到β-酮脂酰CoA反应，人类有 两种不同的酶：一种用于短链L-3-羟酰基CoA底物 （SCHAD）和长链代谢物（LCHAD）。初步的X光数据显示 确定了SCHAD的辅酶位点。现在的重要目标是 表征定义脂肪酸来源的分子结构 链特异性。这将通过与以下相关的SCHAD的X射线分析来完成： 合适的基质。在第二阶段中， 多功能蛋白将在E.大肠杆菌，结晶，和3D 通过衍射方法确定结构。 在穿梭细胞内蛋白质结构研究的继续中， 脂肪酸和类维生素A，诱变，滴定量热法和x射线 晶体学将用于探索配体特异性。一种方法将 质子与静电结合联合收割机实验测定 特征pKs的计算。

DESCRIPTION (Adapted from abstract): The long-term objective is to provide data on the interaction of lipids with transport proteins or enzymes. To do this, the molecular structure of lipid-containing macromolecules will be used to describes lipid-protein interactions. A nearly complete study of lipovitellin has led to similar studies of microsomal triglyceride transfer protein (MTP), which is involved in assembly of the serum lipoproteins. A major aim is to compete the crystal structure of a complex of MTP with protein disulfide isomerase. For lipovitellin, new x-ray measurements have provided preliminary evidence about the conformation of 20 bound acyl chains. The new data will be refined and an effort will be made to reconstruct the entire domain of phospholipids present in lipovitellin. Attempts to crystallize apo A1, the principal protein component of HDL will be continued. In the beta-oxidation spiral, more than one enzyme appears to be associated with each reaction. For the beta-OH to beta-ketoacyl CoA reaction, humans have two different enzymes: one for short chain L-3-hydroxyacyl CoA substrates (SCHAD) and one for long chain metabolites (LCHAD). Preliminary x-ray data have identified the coenzyme site of SCHAD. The important goal now is to characterize the molecular structure that defines the origin of fatty acid chain specificity. This will be done by x-ray analyses of SCHAD associated with appropriate substrates. In a second stage, the LCHAD segment of a multifunctional protein will be expressed in E. coli, crystallized, and the 3D structure determined by diffraction methods. In a continuation of structural studies of intracellular proteins for shuttling fatty acids and retinoids, mutagenesis, titration calorimetry, and x-ray crystallography will be used to explore ligand specificity. One approach will combine experimental determination of proton binding with electrostatic calculations of characteristic pKs.