Site-specific N-glycosylation of chicken serum IgG.
Site-specific N-glycosylation of chicken serum IgG.
复制标题
鸡血清 IgG 的位点特异性 N-糖基化。
DOI：
10.1093/glycob/cwh031
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发表时间：
2004
期刊：
影响因子：
4.3
通讯作者：
Lee,YuanC
中科院分区：
文献类型：
--
作者：
Suzuki,Noriko;Lee,YuanC
禽血清免疫球蛋白（IgG 或 IgY）在功能上与哺乳动物 IgG 相同，但在其重 (H) 链中多了一个恒定区 (CH2)。在鸡 IgG 中，每个 H 链包含两个位于 CH2 和 CH3 结构域上的潜在 N-糖基化位点。为了阐明禽类 IgG 上的 N-糖基化特征，我们通过 2-氨基吡啶 (PA) 衍生化分析鸡血清 IgG 中的 N-聚糖，并通过 HPLC 和 MALDI-TOF-MS 进行鉴定。 N-聚糖有两种类型：(1)高甘露糖型寡糖(单葡糖基化26.8%，其他10.5%)和(2)双触角复合型寡糖(中性，29.9%；单唾液酸，29.3%；二唾液酸，3.7%)，以总N-聚糖的摩尔数计。为了研究不同N-聚糖的位点特异性定位，用木瓜蛋白酶消化鸡血清IgG并分离成Fab [包含可变区(VH + VL) + CH1 + CL]和Fc (包含CH3 + CH4)片段。 Con A 仅对 Fc (CH3 + CH4) 进行染色，RCA-I 仅对 Fab 片段进行染色，表明高甘露糖型寡糖位于 Fc (CH3 + CH4) 片段上，并且 Fab 的可变区包含复合型 N-聚糖。鸡 IgG 糖肽的 MS 分析表明，鸡 CH3 结构域（结构与哺乳动物 CH2 结构域相同）仅包含高甘露糖型寡糖，而鸡 CH2 结构域仅包含复合型 N-聚糖。禽类 IgG 上的 N-糖基化模式与哺乳动物 IgE 中的 N-糖基化模式比 IgG 更相似，大概反映了与哺乳动物 IgE 的结构相似性。
Avian serum immunoglobulin (IgG or IgY) is functionally equivalent to mammalian IgG but has one additional constant region domain (CH2) in its heavy (H) chain. In chicken IgG, each H-chain contains two potentialN-glycosylation sites located on CH2 and CH3 domains. To clarify characteristics ofN-glycosylation on avian IgG, we analyzeN-glycans from chicken serum IgG by derivatization with 2-aminopyridine (PA) and identified by HPLC and MALDI-TOF-MS. There were two types ofN-glycans: (1) high-mannose-type oligosaccharides (monoglucosylated 26.8%, others 10.5%) and (2) biantennary complex-type oligosaccharides (neutral, 29.9%; monosialyl, 29.3%; disialyl, 3.7%) on molar basis of totalN-glycans. To investigate the site-specific localization of differentN-glycans, chicken serum IgG was digested with papain and separated into Fab [containing variable regions (VH + VL) + CH1 + CL] and Fc (containing CH3 + CH4) fragments. Con A stained only Fc (CH3 + CH4) and RCA-I stained only Fab fractions, suggesting that high-mannose-type oligosaccharides were located on Fc (CH3 + CH4) fragments, and variable regions of Fab contains complex-typeN-glycans. MS analysis of chicken IgG-glycopeptides revealed that chicken CH3 domain (structurally equivalent to mammalian CH2 domain) contained only high-mannose-type oligosaccharides, whereas chicken CH2 domain contained only complex-typeN-glycans. TheN-glycosylation pattern on avian IgG is more analogous to that in mammalian IgE than IgG, presumably reflecting the structural similarity to mammalian IgE.