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    Sequence-to-structure dependence of isolated IgG Fc complex biantennary N-glycans: a molecular dynamics study


    Harbison, Aoife M. and Brosnan, Lorna P. and Fenlon, Keith and Fadda, Elisa (2018) Sequence-to-structure dependence of isolated IgG Fc complex biantennary N-glycans: a molecular dynamics study. Glycobiology, 29 (1). pp. 94-103. ISSN 0959-6658

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    Abstract

    Fc glycosylation of human immunoglobulins G (IgGs) is essential for their structural integrity and activity. Interestingly, the specific nature of the Fc glycoforms is known to modulate the IgG effector function and inflammatory properties. Indeed, while core-fucosylation of IgG Fc-glycans greatly affects the antibody-dependent cell-mediated cytotoxicity function, with obvious repercussions in the design of therapeutic antibodies, sialylation can reverse the antibody inflammatory response, and galactosylation levels have been linked to aging, to the onset of inflammation, and to the predisposition to rheumatoid arthritis. Within the framework of a structure-to-function relationship, we have studied the role of the N-glycan sequence on its intrinsic conformational propensity. Here we report the results of a systematic study, based on extensive molecular dynamics simulations in excess of 62 μs of cumulative simulation time, on the effect of sequence on the structure and dynamics of increasingly larger, complex biantennary N-glycoforms isolated from the protein, i.e. from chitobiose to the larger N-glycan species commonly found in the Fc region of human IgGs. Our results show that while core fucosylation and sialylation do not affect the intrinsic dynamics of the unlinked N-glycans, galactosylation of the α(1–6) arm shifts dramatically its conformational equilibrium from an outstretched to a folded conformation. These findings are in agreement with and can help rationalize recent experimental evidence showing a differential recognition of positional isomers in glycan array data and also the preference of sialyltransferase for the more accessible, outstretched α(1–3) arm in both isolated, and Fc-bound N-glycans.

    Item Type: Article
    Keywords: Fc-glycosylation; glycoinformatics; IgG; molecular dynamics; N-glycans; Structural Biology;
    Academic Unit: Faculty of Science and Engineering > Chemistry
    Faculty of Science and Engineering > Research Institutes > Hamilton Institute
    Item ID: 12535
    Identification Number: https://doi.org/10.1093/glycob/cwy097
    Depositing User: Elisa Fadda
    Date Deposited: 06 Mar 2020 17:04
    Journal or Publication Title: Glycobiology
    Publisher: Oxford University Press
    Refereed: Yes
    URI:

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