Figure 4. Pattern-2 structural difference is associated with the absence of the R1411:D771 salt bridge.
Distance measurement between R1411 (orange) and D771 (maroon) found in the (A) 2008b and (B) 2013 HA homology models. All amino acid residues indicated are in a wireframe structure. All measurements are indicated in Å. HA structural difference is shaded in gray.