A NOVEL SIALYLATED N ACETYLGALACTOSAMINE-CONTAINING OLIGOSACCHARIDE IS THE MAJOR COMPLEX-TYPE STRUCTURE PRESENT IN BOWES MELANOMA TISSUE PLASMINOGEN ACTIVATOR
A NOVEL SIALYLATED N ACETYLGALACTOSAMINE-CONTAINING OLIGOSACCHARIDE IS THE MAJOR COMPLEX-TYPE STRUCTURE PRESENT IN BOWES MELANOMA TISSUE PLASMINOGEN ACTIVATOR
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DOI：
10.1093/glycob/1.2.173
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发表时间：
1991-01-01
期刊：
影响因子：
4.3
通讯作者：
DELL A
中科院分区：
文献类型：
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作者：
CHAN A L;MORRIS H R;DELL A
我们采用快原子轰击质谱 (FAB-MS) 筛选 Bowes 黑色素瘤组织纤溶酶原激活剂 (mt-PA) 的 N 连接寡糖，以及中国仓鼠卵巢细胞 (rt-PA) 和基因富集的黑色素瘤细胞系 (rmt-PA) 产生的重组 t-PA。这些研究证实了已发表的 rt-PA 结构，但与报道的 mt-PA 的一些结构不一致。在后一种糖蛋白中，我们鉴定出一种新的结构，作为连接到 Asn-184 和 Asn-448 的主要寡糖。这是一种双触角寡糖，由岩藻糖基化三甘露糖基核心组成，其上附有两个 GalNAc(1.fwdarw.4)GlcNAc 触角，其中一个触角带有连接在 GalNAc 6 位的唾液酸。次要成分在两个触角或两个触角上均被唾液酸化。唾液酸化的 GalNAc 部分在 N 连接糖蛋白中是独特的。 rmt-PA 中的大多数复杂结构在 Asn-184 和 Asn-448 处均含有 N-乙酰基乳糖胺部分，而新型寡糖作为 Asn-184 位点的次要成分出现。这项研究证明了基于高场两扇区 FAB-MS 的质谱策略在天然和重组糖蛋白结构解析方面的强大功能。
We have employed fast atom bombardment mass spectrometry (FAB-MS) to screen the N-linked oligosaccharides of Bowes melanoma tissue plasminogen activator (mt-PA), and recombinant t-PAs produced by Chinese hamster ovary cells (rt-PA) and by a gene-enriched melanoma cell line (rmt-PA). These studies have confirmed the published structures for rt-PA, but are not in agreement with some of the structures reported for mt-PA. In the latter glycoprotein we have identified a novel structure as the major oligosaccharide attached to Asn-184 and Asn-448. This is a biantennary oligosaccharide consisting of a fucosylated trimannosyl core to which are attached two GalNAc(1.fwdarw.4)GlcNAc antennae, one of which carries a sialic acid linked at the 6-position of the GalNAc. Minor constituents are sialylated on both or neither antennae. The sialylated GalNAc moiety is unique in N-linked glycoproteins. The majority of complex structures in rmt-PA contain N-acetyllactosamine moieties at both the Asn-184 and Asn-448 with the novel oligosaccharide occurring as a minor component at the Asn-184 site. This study demonstrates the power of mass spectrometric strategies based on high-field two-sector FAB-MS for structure elucidations of natural and recombinant glycoproteins.