Barchi Joseph J
Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, 21702.
Biopolymers. 2013 Oct;99(10):713-23. doi: 10.1002/bip.22313.
Mucins are very high molecular weight glycoproteins that form a "mucus" barrier at the surface of epithelial cells. They are heavily glycosylated with O-linked glycans that are involved in myriad cellular functions, including protection from external changes in pH, ion flux and reactive oxygen species. Aberrations in mucin expression and their glycan constitution have been associated with many disease states including gastritis, pulmonary disorders and cancer. High resolution structural information on mucins is lacking due to their complexity, in particular their large size and the many variants of O-linked glycans produced in their biosynthesis. This review discusses the structures of glycopeptides that contain "mucin-type" glycosylation, and concentrates primarily on data obtained by NMR spectroscopy. The effect of the glycan on the peptide backbone, the features that have shown to be common to this type of glycosylation and the differences of glycosylation at serine and threonine residues are the major topics of discussion.
黏蛋白是非常高分子量的糖蛋白，它们在上皮细胞表面形成“黏液”屏障。它们被O-连接聚糖高度糖基化，这些聚糖参与了无数细胞功能，包括保护细胞免受外部pH值、离子通量和活性氧的变化影响。黏蛋白表达及其聚糖组成的异常与许多疾病状态相关，包括胃炎、肺部疾病和癌症。由于黏蛋白的复杂性，特别是其大尺寸以及生物合成过程中产生的多种O-连接聚糖变体，目前缺乏关于黏蛋白的高分辨率结构信息。本综述讨论了含有“黏蛋白型”糖基化的糖肽结构，主要集中于通过核磁共振光谱获得的数据。聚糖对肽主链的影响、已证明是这种糖基化类型共有的特征以及丝氨酸和苏氨酸残基糖基化的差异是讨论的主要话题。
