CARBOHYDRATE AND GLYCOPEPTIDE INTERACTIONS WITH LECTINS

正常和转化的表面上的碳水化合物 细胞在各种生物中作为受体决定因素发挥作用 识别过程。这三类共价结合 分子被称为高甘露糖、复合型和杂化型。 低聚糖，每个都形成不同的结构。 尽管它们作为细胞表面受体发挥作用，但人们对此知之甚少。 这些低聚糖的分子结合特性， 除了它们是糖基酶的底物，而且它们结合在一起 敬凝集素。凝集素是结合在一起的植物和动物蛋白质。 特定的碳水化合物决定因素，而不修改它们。 植物凝集素具有广泛的生物学应用， 包括它们在探索结构和动力学方面的应用 正常细胞和转化细胞的细胞膜特性。 在更广泛使用的植物金属凝集素中有 刀豆蛋白A(ConA)，小扁豆(Lch)，豌豆(PSA)，大豆 (SBA)和利马豆(LBL)凝集素，它们都具有不同的 结合的特异性，以及一系列不同的生物活性。 我们的目标是确定分子结合 高甘露糖复合型和杂交型的机理 含凝集素的糖肽及其相关的合成寡糖 为了研究其分子识别决定因素 这些细胞表面受体。该化合物的光谱性质 凝集素包括它们结合的金属离子将被研究，因为 金属离子可以作为本征态的报告基团 监测碳水化合物与 蛋白质。我们发现了一种制备金属离子的方法 LCH和PSA的衍生物现在使研究 这两种凝集素的相互作用，除了其他凝集素外， 通过各种光谱技术与碳水化合物结合， 包括核磁共振、电子自旋 共振(EPR)、自旋回波和圆二向色性(CD) 测量。核磁共振技术将包括溶剂质子核磁共振 色散测量，以及高分辨率1H、19F、13C和 ~(113)Cd核磁共振实验。这些研究将提供直接的数据 关于这几类重要分子的分子结合性质 细胞表面碳水化合物，以及结合特性 凝集素。

Carbohydrates on the surface of both normal and transformed cells function as receptor determinants in various biological recognition processes. Three classes of these covalently bound molecules are called high mannose, complex, and hybrid type oligosaccharides, which each form a variety of structures. Although they function as cell surface receptors, little is known of the molecular binding properties of these oligosaccharides, other than they are substrates for glycosylases, and that they bind to lectins. Lectins are plant and animal proteins which bind to specific carbohydrate determinants without modifying them. Plant lectins have a wide number of biological applications, including their use in exploring the structure and dynamic properties of the membranes of normal and transformed cells. Among the more widely employed plant metallolectins are Concanavalin A (Con A), and the lentil (LcH), pea (PSA), soybean (SBA) and lima-bean (LBL) lectins, all of which possess different binding specificities, and a range of different biological activities. Our objectives are to determine the molecular binding mechanisms of high mannose complex, and hybrid type glycopeptides and related synthetic oligosaccharides with lectins in order to investigate the molecular recognition determinants of these cell surface receptors. The spectroscopic properties of the lectins including their bound metal ions will be investigated, since the metal ions can serve as intrinsic reporter groups for monitoring the interactions of the carbohydrates with the proteins. Our discovery of a method of preparing metal ion derivatives of LcH and PSA now makes in possible to study the interactions of these two lectins, in addition to the other lectins, with the carbohydrates by a variety of spectroscopic techniques, including nuclear magnetic resonance (NMR), electron spin resonance (EPR) and spin-echo, and circular dichroism (CD) measurements. NMR techniques will include solvent proton NMR dispersion measurements, and high resolution 1H, 19F, 13C, and 113Cd NMR experiments. These studies will provide direct data on the molecular binding properties of these important classes of cell surface carbohydrates, as well as the binding specificities of the lectins.