Although we used accelerated 4-O-glucopyranosyl-5-O-methylvisamminol stress conditions of high protein concentration and high temperature for this set of FRET experiments, we expect that our results will be representative for lower temperature conditions after a longer stress time. We established a mathematical model that successfully predicts longterm aggregation data based on accelerated aggregation experiments. The fluorophores we used in our experiments as site-specific reporters of structural dynamics are extrinsically attached probes with properties on their own. However, the fact that labeled antibodies retain most of their activity indicates that the fluorophores do not perturb the structure of the antibodies. With the consistent comparison of fluorescence across all four variants, we believe our results represent the variants�� site dynamics and not the probes�� intrinsic properties. Moreover, when we label K326C in the antibody wild type and in the Variant FS background, we observe two times more aggregates in Variant K326C FS than in Variant K326C WT, consistent with the lower Aescin-IIA stability of Variant FS compared to WT. This result suggests that the aggregation patterns we observe of our labeled samples are a function of the unlabeled protein stability, and not of the attached fluorophore. Many mutations have been generated in the Fc region mostly for the purpose of modulating Fc Receptor binding. Thus, there is abundant literature on amino acid mutations known to affect receptor binding or glycosylation pattern. However, few CH2 mutations have been used in stability analysis. Variant FS and FY permit elucidation of the role of protein-carbohydrate interactions in CH2 domain stability. Unlike other destabilized CH2 antibody variants such as deglycosylated variants, Variant FS is more fully glycosylated. Similarly to the finding that deglycosylated human IgG shows higher protein hydrophobicity exposure, Variant FS is more susceptible to proteolytic digest, indicative of higher exposure of protein surface than wild type.The different Glu-C digestive pattern of deglycosylated wild type and Variant FS suggests the presence of structural differences apart from carbohydrateprotein binding.