Chemoenzymatic Fc Glycosylation via Engineered Aldehyde Tags

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• 作者：Elizabeth L. Smith ; John P. Giddens ; Anthony T. Iavarone ; Kamil Godula ; Lai-Xi Wang ; Carolyn R. Bertozzi
• 刊名：Bioconjugate Chemistry
• 出版年：2014
• 出版时间：April 16, 2014
• 年：2014
• 卷：25
• 期：4
• 页码：788-795
• 全文大小：345K
• 年卷期：v.25,no.4(April 16, 2014)
• ISSN：1520-4812

文摘

Glycoproteins with chemically defined glycosylation sites and structures are important biopharmaceutical targets and critical tools for glycobiology. One approach toward constructing such molecules involves chemical glycosylation of aldehyde-tagged proteins. Here, we report the installation of a genetically encoded aldehyde tag at the internal glycosylation site of the crystallizable fragment (Fc) of IgG1. We replaced the natural Fc N-glycosylation sequon with a five amino-acid sequence that was efficiently converted by recombinant formylglycine generating enzyme in vitro, thereby introducing aldehyde groups for subsequent chemical elaboration. Oxime-linked glycoconjugates were synthesized by conjugating aminooxy N-acetylglucosamine to the modified Fc followed by enzymatic transfer of complex N-glycans from corresponding glycan oxazolines by an EndoS-derived glycosynthase. In this manner we generated specific Fc glycoforms without relying on natural protein glycosylation machineries.