NMR assignments of the N-glycans of the Fc fragment of mouse immunoglobulin G2b glycoprotein
NMR assignments of the N-glycans of the Fc fragment of mouse immunoglobulin G2b glycoprotein
复制标题
小鼠免疫球蛋白 G2b 糖蛋白 Fc 片段的 N-聚糖的 NMR 分配
DOI：
10.1007/s12104-020-10004-5
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发表时间：
2021
影响因子：
0.9
通讯作者：
Kato Koichi
中科院分区：
文献类型：
--
作者：
Yanaka Saeko;Yamaguchi Yoshiki;Takizawa Takeshi;Miyanoiri Yohei;Yogo Rina;Shimada Ichio;Kato Koichi
免疫球蛋白G （IgG）的Fc部分通过与Fcγ受体和补体组分C1q相互作用，促进免疫系统中的防御效应功能。这些相互作用严重依赖于每个CH2结构域Asn297的n-糖基化，其中双天线络合物型低聚糖含有微异质性，主要是由于存在或不存在非还原末端半乳糖残基。Fc的晶体结构表明，一对n -聚糖位于两个CH2结构域之间。在这里，我们利用哺乳动物细胞的代谢同位素标记技术，对分子质量为54 kDa的小鼠IgG2b-Fc糖型进行了溶液结构表征。基于n -聚糖和Fc多肽骨架的光谱分配，我们探讨了n -聚糖修饰，特别是酶解半乳糖基化对Fc的构象扰动。结果表明，去半乳糖基化通过聚糖-蛋白相互作用的重排在结构上扰乱了Fc区。IgG2b-Fc糖蛋白的光谱分配将为其在溶液中动态构象和与效应分子相互作用的核磁共振研究提供基础。
The Fc portion of immunoglobulin G (IgG) promotes defensive effector functions in the immune system by interacting with Fcγ receptors and complement component C1q. These interactions critically depend onN-glycosylation at Asn297 of each CH2 domain, where biantennary complex-type oligosaccharides contain microheterogeneities resulting primarily from the presence or absence of non-reducing terminal galactose residues. Crystal structures of Fc have shown that a pair ofN-glycans is located between the two CH2 domains. Here we applied our metabolic isotope labeling technique using mammalian cells forin-solutionstructural characterization of mouse IgG2b-Fc glycoforms with a molecular mass of 54 kDa. Based on spectral assignments of theN-glycans as well as polypeptide backbones of Fc, we probed conformational perturbations of Fc induced byN-glycan trimming, especially enzymatic degalactosylation. The results indicated that degalactosylation structurally perturbed the Fc region through rearrangement of glycan-protein interactions. The spectral assignments of IgG2b-Fc glycoprotein will provide the basis for NMR investigation of its dynamic conformations and interactions with effector molecules in solution.