Chemical and Structural Analysis of an Antibody Folding Intermediate Trapped during Glycan Biosynthesis

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• 作者：Thomas A. Bowden ; Kavitha Baruah ; Charlotte H. Coles ; David J. Harvey ; Xiaojie Yu ; Byeong-Doo Song ; David I. Stuart ; A. Radu Aricescu ; Christopher N. Scanlan ; E. Yvonne Jones ; Max Crispin
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：October 24, 2012
• 年：2012
• 卷：134
• 期：42
• 页码：17554-17563
• 全文大小：621K
• 年卷期：v.134,no.42(October 24, 2012)
• ISSN：1520-5126

文摘

Human IgG Fc glycosylation modulates immunological effector functions such as antibody-dependent cellular cytotoxicity and phagocytosis. Engineering of Fc glycans therefore enables fine-tuning of the therapeutic properties of monoclonal antibodies. The N-linked glycans of Fc are typically complex-type, forming a network of noncovalent interactions along the protein surface of the C纬2 domain. Here, we manipulate the mammalian glycan-processing pathway to trap IgG1 Fc at sequential stages of maturation, from oligomannose- to hybrid- to complex-type glycans, and show that the Fc is structurally stabilized following the transition of glycans from their hybrid- to complex-type state. X-ray crystallographic analysis of this hybrid-type intermediate reveals that N-linked glycans undergo conformational changes upon maturation, including a flip within the trimannosyl core. Our crystal structure of this intermediate reveals a molecular basis for antibody biogenesis and provides a template for the structure-guided engineering of the protein鈥揼lycan interface of therapeutic antibodies.