N-glycans on the cell surface provide distinct signatures that are recognized by different glycan-binding proteins (GBPs) and pathogens. Most glycans in humans are asymmetric and isomeric, yet their biological functions are not well understood due to their lack of availability for studies. In this work, we have developed an improved strategy for asymmetric N-glycan assembly and diversification using designed common core substrates prepared chemically for selective enzymatic fucosylation and sialylation. The resulting 26 well-defined glycans that carry the sialic acid residue on different antennae were used in a microarray as a representative application to profile the binding specificity of hemagglutinin (HA) from the avian influenza virus (H5N2). We found distinct binding affinity for the Neu5Ac-Gal epitope linked to the N-acetylglucosamine (GlcNAc) of different branches and only a minor effect in binding for the terminal galactose on different branches. Overall, the microarray analysis showed branch-biased and context-based recognition patterns.

中文翻译：

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通过选择性酶促糖基化反应合成不对称的N-糖类作为通用核心底物，实现结构多样化。

细胞表面的N-聚糖具有独特的特征，可被不同的聚糖结合蛋白（GBP）和病原体识别。人类中的大多数聚糖是不对称和异构的，但由于缺乏研究性，人们对其生物学功能的了解还不够。在这项工作中，我们开发了一种改进的N不对称策略-聚糖的组装和多样化，使用设计的通用核心底物进行化学制备，用于选择性酶促岩藻糖基化和唾液酸化。在微阵列中使用所得的26个在不同触角上带有唾液酸残基的明确定义的聚糖作为代表性应用，以分析禽流感病毒（H5N2）的血凝素（HA）的结合特异性。我们发现与Neu5Ac-Gal表位连接到不同分支的N-乙酰氨基葡萄糖（GlcNAc）有独特的结合亲和力，并且在结合不同分支上的末端半乳糖方面只有很小的作用。总体而言，微阵列分析显示了分支偏向和基于上下文的识别模式。