Structural analysis of antigenic variation and adaptive evolution of the H5N1 neuraminidase gene
Fig 2
Structural superimposition of nine avian influenza A neuraminidase (NA) subtypes (N1–N9) illustrating conserved and variable regions essential for identifying Family-Specific Positions (FSPs).
(A) Shows the overlay of NA subtypes as cartoons highlighting shared folds and subtype-specific conformational differences. Structures are color-coded for clarity and as follows; 2HTY (Beige/Tan), 1NN2 (Sky Blue), 4HZY (Salmon or Light Coral), 2HTV (Light Green), 3SAL (Golden Yellow/Amber), 4QN4 (Deep Pink/ Fuchsia), 4QN3 (Light grey), 2HT5 (Pale Magenta), and 7NN9 (deep blue). (B) Zooms in on the conserved active site and 150-loop residues (labeled by 2HTY numbering), demonstrating their critical and consistent roles across all subtypes, which supports functional analysis and FSP identification via the ZEBRA2 algorithm.