Fig 5. The epitope of Ab10 was determined by alanine mutant analysis.

The conformational epitope of Ab10 antibody on the Gn glycoprotein ectodomain was determined by measuring antibody binding activity to recombinant mutant proteins with amino acid residues that were substituted with alanine at residues corresponding to 315–389. (A) Epitopes predicted by cross-linker assisted mass spectrometry are shown in red, and alanine substituted residues that affected Ab10 antibody binding are shown in purple. The overlapping domain II (blue annotation) and region upstream of the stem region (gray annotation) are also indicated. (B) The reactivity of Ab10 to each alanine mutant is represented as relative reactivity, which was calculated using absorbance values (Abs) as follows: % Relative reactivity = [100 × {(Abs of mutant captured by Ab10) / (Abs of mutant captured by HA antibody)} / {(Abs of wildtype captured by Ab10) / (Abs of wildtype captured by HA antibody)}]. Bars indicate the mean and standard deviation (s.d.).