MUCIN GLYCOPROTEIN CONFORMATION

这个提议的目标是阐明分子间的相互作用 和结构，引起高度延伸的构象的 粘蛋白和粘蛋白样糖蛋白中的重度O-糖基化结构域。 这种O-糖基化结构域，通过硬化和延伸肽 核心，有助于粘蛋白的粘弹性， 呼吸道、消化道和泌尿生殖道的表面。 类似的重度O-糖基化结构域也存在于 几种膜相关糖蛋白的胞外部分。 这些结构域的作用是将球状酶或受体束缚在细胞上方 作为细胞表面涂层，其可以调节免疫 监视和识别。 分子动力学建模和NMR方法将用于确定 一系列粘蛋白和重组蛋白的构象和动力学 不同一级结构的DNA衍生的O-连接糖肽， 糖基化模式 肽序列的作用，特别是 Gly和Pro的存在以及糖基化Ser和Thr的聚集 将研究它们对糖肽构象的影响， 链延伸和刚性。 这些研究将使我们能够确定 特别是糖基化如何影响肽构象和作用 碳水化合物-肽和碳水化合物-碳水化合物的相互作用。 这些结果将有助于更好地理解碳水化合物-蛋白质 相互作用和最终的改进，在计算机建模， 糖蛋白 溶液环境的影响和可能性 链间碳水化合物-碳水化合物相互作用的影响也可以是 考察 这些研究是我们长期目标的组成部分， 确定粘蛋白的物理性质的分子基础 以及参与水化和分泌 粘蛋白。 我们的主要实验目标是：1）表征和执行NM 一系列O-连接短肽的构象分析 衍生自部分去糖基化的猪颌下粘蛋白，2） 进行分子建模和分子动力学计算， 比较，和3）使用重组DNA技术表达 另外的独特肽序列的O-连接糖肽， 在转染的中国仓鼠卵巢（CHO）细胞中，

The goals of this proposal are to elucidate the molecular interactions and structures that give rise to the highly extended conformations of the heavily O-glycosylated domains in mucins and mucin-like glycoproteins. Such O-glycosylated domains, by stiffening and extending the peptide core, contribute to the viscoelastic properties of mucins which protect the surfaces of the respiratory, digestive and urogenital tracts. Similar heavily O-glycosylated domains are also found in the extracellular portions of several membrane- associated glycoproteins. These domains act to tether globular enzymes or receptors above the cell surface and as cell surface coatings which may modulate immune surveillance and recognition. Molecular dynamics modeling and NMR approaches will be used to determine the conformations and dynamics of a series of mucin and recombinant DNA-derived O-linked glycopeptides of different primary structures and glycosylation patterns. The role of peptide sequence, in particular the presence of Gly and Pro, and the clustering of glycosylated Ser and Thr will be studied with regard to their effect on glycopeptide conformation, chain extension and stiffness. These studies will allow us to determine specifically how glycosylation affects peptide conformation and the roles of carbohydrate-peptide and carbohydrate-carbohydrate interactions. These results will lead to a better understanding of carbohydrate-protein interactions and eventual improvements in the computer modeling of glycoproteins. The effects of solution environment and the possibility of inter-chain carbohydrate-carbohydrate interactions may also be examined. These studies are an integral part of our long range goals of determining both the molecular basis of the physical properties of mucins and the molecular processes involved in the hydration and secretion of mucins. Our major experimental objectives are to: 1) Characterize and perform NM conformational analyses on a series of short O-linked glycopeptides derived from partially deglycosylated porcine submaxillary mucin, 2) To perform molecular modeling and molecular dynamics calculations for comparison, and 3) to use recombinant DNA techniques to express additional O-linked glycopeptides of unique peptide sequences, unavailable from PSM, in transfected Chinese hamster ovary (CHO) cells.