Résumé
Antibody-dependent cellular cytotoxicity relies on the interaction between the Fc re-gion of immunoglobulin G1 (IgG1) and the CD16a receptor. While removal of core fu-cosylation on Fc and introduction of the DFTE mutation set (S239D, H268F, S324T, I332E) are known to enhance CD16a binding, the detailed contributions of these engi-neered sites in solution remain incompletely defined. Here, we employed 1 µs molecu-lar dynamics simulations to map, at atomic resolution, the interaction networks stabi-lizing pre-formed Fc-CD16a complexes, including afucosylated Fc-wild-type, DFTE-engineered, Fc-fucosylated, and asymmetrically engineered Fc variants. Our re-sults show that only S239D, present on both Fc chains, and H268F on chain A consist-ently contribute to stabilizing the CD16a interface, while I332E does not form persis-tent interactions. Glycan–protein contacts are primarily intrachain, with transient in-terchain glycan–glycan interactions not contributing significantly to complex stability. Fucosylation on Fc significantly reduces binding stability by disrupting peripheral in-teractions and critical glycan-mediated contacts. Notably, the asymmetric Fc variant, in which the two heavy chains carry distinct sets of substitutions, retains high-affinity binding despite lacking S239D and carrying core fucose, through a novel hydrophobic cluster and reinforced peripheral electrostatic interactions. Altogether, these findings provide a quantitative framework for how targeted mutations and fucose modifica-tions remodel Fc-CD16a interactions, offering insights for the rational design of next-generation therapeutic antibodies.