Discovery of a lectin domain that regulates enzyme activity in mouse N-acetylglucosaminyltransferase-IVa (MGAT4A).
Discovery of a lectin domain that regulates enzyme activity in mouse N-acetylglucosaminyltransferase-IVa (MGAT4A).
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DOI：
10.1038/s42003-022-03661-w
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发表时间：
2022-07-19
影响因子：
5.9
通讯作者：
Kizuka Y
中科院分区：
文献类型：
--
作者：
Nagae M;Hirata T;Tateno H;Mishra SK;Manabe N;Osada N;Tokoro Y;Yamaguchi Y;Doerksen RJ;Shimizu T;Kizuka Y
N-糖基化是一种常见的翻译后修饰，N-聚糖中GlcNAc分支的数量影响糖蛋白功能。N-乙酰葡糖胺转移酶-IVa（GnT-IVa，也称为MGAT 4A）在N-聚糖的α1-3甘露糖臂上形成β1-4 GlcNAc分支。GnT-IVa的下调或缺失通过胰腺β细胞中葡萄糖转运蛋白-2的失调引起糖尿病表型。尽管GnT-IVa的生理重要性，其结构和催化机制知之甚少。在这里，我们确定在小鼠GnT-IVa的C-末端区域的凝集素结构域。凝集素结构域的晶体结构显示出与细菌GlcNAc结合凝集素的结构相似性。使用157个聚糖和溶液NMR的综合聚糖结合测定揭示GnT-IVa凝集素结构域选择性地与具有β1-4 GlcNAc分支的产物N-聚糖相互作用。对糖识别起关键作用的残基的点突变损害酶活性，表明凝集素结构域是有效催化反应的调节亚基。我们的研究结果提供了深入了解N-聚糖的分支结构是如何生物合成的。X射线晶体学与NMR和计算机建模揭示了GnTIVa的结构和催化机制，GnTIVa是参与GlcNAc分支合成的关键酶，具有调节其催化活性的不寻常的C-末端凝集素结构域。
N-Glycosylation is a common post-translational modification, and the number of GlcNAc branches in N-glycans impacts glycoprotein functions. N-Acetylglucosaminyltransferase-IVa (GnT-IVa, also designated as MGAT4A) forms a β1-4 GlcNAc branch on the α1-3 mannose arm in N-glycans. Downregulation or loss of GnT-IVa causes diabetic phenotypes by dysregulating glucose transporter-2 in pancreatic β-cells. Despite the physiological importance of GnT-IVa, its structure and catalytic mechanism are poorly understood. Here, we identify the lectin domain in mouse GnT-IVa’s C-terminal region. The crystal structure of the lectin domain shows structural similarity to a bacterial GlcNAc-binding lectin. Comprehensive glycan binding assay using 157 glycans and solution NMR reveal that the GnT-IVa lectin domain selectively interacts with the product N-glycans having a β1-4 GlcNAc branch. Point mutation of the residue critical to sugar recognition impairs the enzymatic activity, suggesting that the lectin domain is a regulatory subunit for efficient catalytic reaction. Our findings provide insights into how branching structures of N-glycans are biosynthesized. X-ray crystallography together with NMR and computer modelling shed light on the structure and catalytic mechanism of GnTIVa, a key enzyme involved in GlcNAc branch synthesis, that bears an unusual C-terminal lectin domain that regulates its catalytic activity.
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影响因子：
16.6
作者：
Lira-Navarrete, Erandi;de las Rivas, Matilde;Companon, Ismael;Carmen Pallares, Maria;Kong, Yun;Iglesias-Fernandez, Javier;Bernardes, Goncalo J. L.;Peregrina, Jesus M.;Rovira, Carme;Bernado, Pau;Bruscolini, Pierpaolo;Clausen, Henrik;Lostao, Anabel;Corzana, Francisco;Hurtado-Guerrero, Ramon
通讯作者：
Hurtado-Guerrero, Ramon
影响因子：
14.8
作者：
Kelley LA;Mezulis S;Yates CM;Wass MN;Sternberg MJ
通讯作者：
Sternberg MJ
影响因子：
11.1
作者：
Kizuka Y;Kitazume S;Fujinawa R;Saito T;Iwata N;Saido TC;Nakano M;Yamaguchi Y;Hashimoto Y;Staufenbiel M;Hatsuta H;Murayama S;Manya H;Endo T;Taniguchi N
通讯作者：
Taniguchi N
影响因子：
2.7
作者：
GU, JG;NISHIKAWA, A;TANIGUCHI, N
通讯作者：
TANIGUCHI, N
影响因子：
14.8
作者：
de Las Rivas M;Paul Daniel EJ;Narimatsu Y;Compañón I;Kato K;Hermosilla P;Thureau A;Ceballos-Laita L;Coelho H;Bernadó P;Marcelo F;Hansen L;Maeda R;Lostao A;Corzana F;Clausen H;Gerken TA;Hurtado-Guerrero R
通讯作者：
Hurtado-Guerrero R