Figure 3. Pattern-1 structural differences are ascribable to salt bridge formation involving amino acid residue 114₁.

Distance measurements of amino acid residues 262₁, 264₁, and 265₁ (green) relative to residue 114₁ (violet) found in the (A) 2011 and (B) 2013 HA homology models. All amino acid residues indicated are in a wireframe structure. All measurements are indicated in Å. Interrelationship of HA structural differences (shaded in gray) observed in the (C,E) 2011 and (D,F) 2013 HA homology models are highlighted in green. Amino acid residue 114₁ is indicated in violet.