In conclusion, the flexibility of glycans allows their binding free energy contribution to vary greatly over time and have a big gap between the two systems. Whereas, provided that single point mutations don't cause large conformational changes, the contribution of sugars in the wild type and mutant should be similar. It's hard to sample statistically significant conformations of complexes with sugars at different positions over a limited period of simulation time. In this article we focus on the effect of residue mutations on antibody binding, rather than the role of sugars. Thus, when calculating binding affinities between NTD and antibodies, we excluded the contribution of sugars.