Figure 4

Analysis of Rn specificity. (A) Signal intensities of Cy3-labeled Rn to sialic acid terminal glycans. Comparison of binding to Neu5Ac and Neu5Gc are shown in solid arrows while α-(2 → 3) Neu5Ac and α-(2 → 6) Neu5Ac binding intensities are shown in dotted arrows. Cartoon representations of glycan structures are shown on top of each corresponding arrow. (B) Model of the area near the binding site of HA1 bound to Neu5Ac (PDB ID, 3AHI). Neu5Ac was modified to Neu5Gc and superimposed to the model. (C) HA1 bound to Neu5Ac model (PDB ID, 3AHI) was used and sugar was substituted with α-(2 → 3) Neu5Ac and α-(2 → 6) Neu5Ac (3SiaLac, PDB ID, 4EN6; 6SiaLac, PDB ID, 4EN8). The models of 3SiaLac and 6SiaLac were then placed in the structure of HA1 based on the position of sialic acid.