Tn抗原、sTn抗原和T抗原的结构和合成

The structure and synthesis of Tn antigen, sTn antigen and T antigen

糖基化是蛋白质翻译后修饰主要方式之一。糖基化主要包括N-糖基化和O-糖基化两种方式。肿瘤细胞常常伴随异常的O-糖基化,并且与肿瘤的不良预后具有密切联系。O-聚糖(Tn、s Tn和T抗原)在多种糖基转移酶(T抗原合成酶、唾液酸转移酶等)的帮助下在高尔基体合成。Cosmc是T抗原合成酶唯一的分子伴侣,它可以帮助新合成的T抗原合成酶氨基酸片段正确的折叠,并形成具有生物活性的T抗原合成酶。本文就O-聚糖的结构和一般合成过程做一简要介绍。

Glycosyiation is one of the major posttranslational modifications of proteins. N-glycosyla- tion（Asn-linked） and O-glycosylation （Ser/Thr-linked） are the two main forms. Abnormal O-glycosylation is frequently observed in tumor cells surface, associated with an adverse outcome and poor prognosis in cancer patients. O-glycans （Tn, sTn and T antigen） is synthesized in golgi apparatus with the assist of many glycosyl- transferase （T-synthase, ST6GalNAc-I, etc） and appropriate environment. The unique molecular chaperone of T-synthase is Cosmc, which helps T-synthase fold correctly in endoplasmic reticulum. This paper briefly intro- duces the general synthesis process of O-glycosylation.