Calvete J J, Muñiz-Diaz E
Instituto de Química-Física CSIC, Madrid, Spain.
FEBS Lett. 1993 Aug 9;328(1-2):30-4. doi: 10.1016/0014-5793(93)80959-x.
The human alloantigen system Baka/b is associated with a Ile843-->Ser replacement on platelet glycoprotein IIb, the alpha-subunit of the integrin receptor for fibrinogen (GPIIb/IIIa). Recent immunological studies indicate that sialylated oligosaccharide chain(s) are also implicated in expression of the Baka determinant. Here we show that the GPIIb fragment 704-856 contains the whole Baka epitope, and that chemical cleavage of a single O-linked oligosaccharide chain within this GPIIb domain correlates with the loss of its anti-Baka antibodies binding ability. Ser847 was identified as the O-glycosylation site. Therefore, our results show that the Ser847 modification is responsible for the expression of the GPIIb-specific Baka alloantigen, and provide thus a link between the molecular biology and the immunologic observations.
人类同种异体抗原系统Baka/b与血小板糖蛋白IIb（纤维蛋白原整合素受体α亚基，即GPIIb/IIIa）上的Ile843→Ser置换有关。最近的免疫学研究表明，唾液酸化寡糖链也与Baka决定簇的表达有关。在此我们表明，GPIIb片段704 - 856包含完整的Baka表位，并且该GPIIb结构域内单个O - 连接寡糖链的化学切割与其抗Baka抗体结合能力的丧失相关。Ser847被确定为O - 糖基化位点。因此，我们的结果表明Ser847修饰负责GPIIb特异性Baka同种异体抗原的表达，从而在分子生物学和免疫学观察结果之间建立了联系。
