Figure 3.

NA structural conservation. Structural alignments of all seasonal influenza vaccine included influenza strains in the period 1970-2021.The sequence conservation of Influenza A N1, Influenza A N2 and Influenza B NA amino acid residues was visualized using MUSCLE and shown on a crystal structure of the respective NA subtype using the render by conservation function in CHIMERA. Residues conserved in all sequences of a specific subtype NA are shown in red. Further distinction of conservation is indicated from dark blue (99% conservation) till yellow (1% conservation). Structure representations based on N1: PDB 4B7Q, N2: PDB 4GZX, and IBV NA: PDB 4CPL. Arrows point towards the catalytic site.