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Study on the Interaction of Sugar Chain with Protein Moiety in Immunoglobulin G

免疫球蛋白G中糖链与蛋白质部分相互作用的研究

基本信息

批准号：
06680629
负责人：
FUJII Shigeru
金额：
$ 1.41万
依托单位：
Kansai Medical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06680629/
关键词：
Glycoprotein Structure of Sugar Chain Protein Structure NMR Fluorescent Labeling

项目摘要

Immunoglobulins G normally have one N-liked sugar chain in each heavy subunit, and different molecules contain heterogeneous biantennary complexes. The sugar chains of human IgG1 differ in the distribution of its galactose residues from bovine IgG and human IgG2. In the present study, we examined the branch specificities of beta-galactosidase for free biantennary complexes and for ones of glycoproteins. The specificities for sugar chains of glycoproteins were not necessarily the same to ones for free oligosaccharides. These results suggest that the protein portion interacts with the sugar chains in glycoproteins.The following results were also obtained. (1) Penicillium notatum phospholipase B contained one kind of oligosaccharides and its structure was determined to be a high-mannose type (Man9). (2) The sugar chains of E-cadherin was modified in murine melanoma cells by ectopically-expressed beta1-4 N-acetylglucosaminyltransferase (GnT-III). This modification induced the increased E-cadherin expression. The glycosylated E-cadherin seems to contribute to the suppression of metastasis. (3) A fluorescence assay method for alpha1-6 fucosyltransferase was developed involving a pyridylaminated sugar as a substrate. The sugar chain is linked to an asparagine to keep a ring structure of the reducing end GlcNAc. With this assay method, alpha1-6 fucosyltransferase was purified from porcine brain.

免疫球蛋白G通常在每个重亚单位中都有一条类N糖链，不同的分子含有不同的双天线复合体。人免疫球蛋白的糖链与牛免疫球蛋白和人免疫球蛋白的半乳糖残基分布不同。在本研究中，我们研究了β-半乳糖苷酶对游离双天线复合体和糖蛋白的分支特异性。糖蛋白糖链的特性不一定与游离寡糖的特性相同。这些结果表明，蛋白质部分与糖蛋白中的糖链相互作用。(1)诺氏青霉磷脂酶B含有一种低聚糖，其结构为高甘露糖型(Man9)。(2)异位表达的β1-4 N-乙酰氨基葡萄糖基转移酶(GnT-III)修饰了小鼠黑色素瘤细胞E-钙粘素的糖链。这种修饰诱导了E-钙粘附素的表达增加。糖基化的E-钙粘附素似乎有助于抑制转移。(3)以吡啶层状糖为底物，建立了α1-6岩藻糖基转移酶的荧光分析方法。糖链连接到天冬酰胺以保持还原型末端GlcNAc的环状结构。用该方法从猪脑中纯化了α1-6岩藻糖基转移酶。