Human low-molecular-weight salivary mucin expresses the sialyl lewisx determinant and has L-selectin ligand activity.
Human low-molecular-weight salivary mucin expresses the sialyl lewisx determinant and has L-selectin ligand activity.
复制标题
DOI：
10.1021/bi972612a
复制
发表时间：
1998-03
期刊：
影响因子：
2.9
通讯作者：
A. Prakobphol;K. Thomsson;Gunnar C. Hansson;Steven D. Rosen;M. Singer;Nancy J. Phillips;K. Medzihradszky;Alma L. Burlingame;Hakon Leffler;Susan J. Fisher
中科院分区：
文献类型：
--
作者：
A. Prakobphol;K. Thomsson;Gunnar C. Hansson;Steven D. Rosen;M. Singer;Nancy J. Phillips;K. Medzihradszky;Alma L. Burlingame;Hakon Leffler;Susan J. Fisher
之前我们表明，低分子量粘蛋白（MG2，由 MUC7 编码）是人类下颌下/舌下唾液的主要成分，是覆盖牙齿表面的细菌受体。在这里，我们测试了这样的假设：其碳水化合物残基的结构包含有关其功能的重要信息。用胰蛋白酶消化纯化的 MG2 (Mr 120 000)，并对所得的 Mr 90 000 片段（主要携带 O 连接寡糖）进行还原性 β 消除。使用核磁共振光谱和质谱对释放的寡糖进行表征。在我们检测到的 41 种不同结构中，最突出的包括 NeuAcalpha2-->3Galbeta1-->3GalNAc-ol（唾液酸-T 抗原）、Galbeta1-->4(Fucalpha1-->3)GlcNAcbeta1-->6(Galbeta1-->3)GalNAc-ol [具有 Lewisx (Lex) 决定簇的 2 型核心]，以及NeuAcalpha2-->3Galbeta1-->4(Fucalpha1-->3)GlcNAcbet a1-->6(Galbeta1-->3) GalNAc-ol [具有唾液酸 Lex (sLex) 决定簇的 2 型核心]。我们还检测到具有一个硫酸基团的二糖、三糖和五糖。 Lex、sLex 和相关的硫酸化结构是选择素的配体，选择素是介导白细胞运输的粘附分子。因此，我们研究了MG2是否是选择素配体。在酶联免疫吸附测定中，L-选择素嵌合体以 Ca2+ 依赖性方式与固定化 MG2 相互作用。 L-选择蛋白嵌合体还与固定在硝化纤维素上的 MG2 结合。总之，这些结果表明 MG2 携带的糖可以指定其一些重要功能，其中可能包括介导口腔中白细胞的相互作用。
Previously we showed that the low-molecular-weight mucin (MG2, encoded by MUC7), a major component of human submandibular/sublingual saliva, is a bacterial receptor that coats the tooth surface. Here we tested the hypothesis that the structure of its carbohydrate residues contains important information about its function. Purified MG2 (Mr 120 000) was digested with trypsin, and the resulting Mr 90 000 fragment, which carried primarily O-linked oligosaccharides, was subjected to reductive beta-elimination. The released oligosaccharides were characterized by using nuclear magnetic resonance spectroscopy and mass spectrometry. Of the 41 different structures we detected, the most prominent included NeuAcalpha2-->3Galbeta1-->3GalNAc-ol (sialyl-T antigen), Galbeta1-->4(Fucalpha1-->3)GlcNAcbeta1-->6(Galbeta1 -->3)GalNAc-ol [type 2 core with Lewisx (Lex) determinant], and NeuAcalpha2-->3Galbeta1-->4(Fucalpha1-->3)GlcNAcbet a1-->6(Galbeta1--> 3) GalNAc-ol [type 2 core with sialyl Lex (sLex) determinant]. We also detected di-, tri-, and pentasaccharides with one sulfate group. Lex, sLex, and related sulfated structures are ligands for selectins, adhesion molecules that mediate leukocyte trafficking. Therefore, we investigated whether MG2 was a selectin ligand. In an enzyme-linked immunosorbent assay, L-selectin chimeras interacted with immobilized MG2 in a Ca2+-dependent manner. L-Selectin chimeras also bound to MG2 immobilized on nitrocellulose. Together, these results suggest that the saccharides that MG2 carries could specify some of its important functions, which may include mediating leukocyte interactions in the oral cavity.