CARBOHYDRATE AND GLYCOPEPTIDE INTERACTIONS WITH LECTINS

碳水化合物在正常和转化的表面 细胞在各种生物学中作为受体决定簇发挥作用。 识别过程。 三种类型的共价键 分子被称为高甘露糖，复杂，和杂交型 寡糖，其各自形成各种结构。 尽管它们作为细胞表面受体发挥作用， 这些寡糖的分子结合特性， 除了它们是糖基化酶的底物， 到凝集素。 凝集素是植物和动物蛋白质， 特定的碳水化合物决定簇而不修饰它们。 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态方面的用途 正常和转化细胞的膜的性质。 在更广泛使用的植物金属凝集素中， 伴刀豆球蛋白A（Con A）、扁豆（LcH）、豌豆（PSA）、大豆 (SBA)和利马豆（LBL）凝集素，所有这些都具有不同的 结合特异性和一系列不同的生物活性。 我们的目标是确定 高甘露糖复合物和杂交型机制 糖肽和相关的具有凝集素的合成寡糖 为了研究的分子识别决定因素 这些细胞表面受体。 的光谱性质 将研究凝集素及其结合的金属离子，因为 金属离子可以作为固有报告基团 监测碳水化合物与 proteins. 我们发现了一种制备金属离子的方法 LcH和PSA的衍生物现在可以研究 这两种凝集素的相互作用，除了其他凝集素， 与碳水化合物通过各种光谱技术， 包括核磁共振（NMR）、电子自旋 共振（EPR）和自旋回波，以及圆二色性（CD） 测量. NMR技术将包括溶剂质子NMR 色散测量和高分辨率1H、19F、13C和 113Cd NMR实验。 这些研究将提供直接数据 对这些重要类别的分子结合特性的研究， 细胞表面碳水化合物，以及结合特异性 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.