The MPB83 antigen from Mycobacterium bovis contains O-linked mannose and (1 → 3)-mannobiose moieties
The MPB83 antigen from Mycobacterium bovis contains O-linked mannose and (1 → 3)-mannobiose moieties
复制标题
DOI：
10.1074/jbc.m207959200
复制
发表时间：
2003-05-02
影响因子：
4.8
通讯作者：
Hewinson, RG
中科院分区：
文献类型：
--
作者：
Michell, SL;Whelan, AO;Hewinson, RG
结核分枝杆菌和牛分枝杆菌，人和牛结核病的病原体，已被报道表达一系列的表面和分泌的糖蛋白，虽然只有其中一个已经进行了详细的结构分析。我们描述了使用遗传系统，结合凝集素结合，以表征碳水化合物部分的第二分枝杆菌糖蛋白，抗原MPB 83从M的多肽骨架的连接点。牛天然MPB 83蛋白和衍生肽的生化和结构分析证明存在连接到两个苏氨酸残基的3个甘露糖单元。甘露糖残基通过（1 -> 3）键连接，与先前在来自M的抗原MPT 32中观察到的（1 -> 2）键相反。结核分枝杆菌中的（1 -> 2）和（1 -> 6）键以及其他分枝杆菌糖脂和多糖中的（1 -> 2）和（1 -> 6）键。M.结核病复合体的发现提高了这些糖蛋白的碳水化合物部分可能参与发病的可能性，或者通过与宿主细胞上的甘露糖受体相互作用，或者作为细胞介导的免疫应答的靶点或调节剂。鉴于这种可能性，分枝杆菌糖蛋白的表征是了解其功能作用和阐明分枝杆菌糖基化机制的一个步骤。
Mycobacterium tuberculosis and Mycobacterium bovis, the causative agents of human and bovine tuberculosis, have been reported to express a range of surface and secreted glycoproteins, although only one of these has been subjected to detailed structural analysis. We describe the use of a genetic system, in conjunction with lectin binding, to characterize the points of attachment of carbohydrate moieties to the polypeptide backbone of a second mycobacterial glycoprotein, antigen MPB83 from M. bovis. Biochemical and structural analysis of the native MPB83 protein and derived peptides demonstrated the presence of 3 mannose units attached to two threonine residues. Mannose residues were joined by a (1 --> 3) linkage, in contrast to the (1 --> 2) linkage previously observed in antigen MPT32 from M. tuberculosis and the (1 --> 2) and (1 --> 6) linkages in other mycobacterial glycolipids and polysaccharides. The identification of glycosylated antigens within the M. tuberculosis complex raises the possibility that the carbohydrate moiety of these glycoproteins might be involved in pathogenesis, either by interaction with mannose receptors on host cells, or as targets or modulators of the cell-mediated immune response. Given such a possibility characterization of mycobacterial glycoproteins is a step toward understanding their functional role and elucidating the mechanisms of mycobacterial glycosylation.