FIG 1.

Escape mutations mapped onto a three-dimensional structure of the NA. The NA of A/California/04/2009 (PDB accession number 3NSS [45]) is depicted as a tetramer with 3 monomers in light gray and one in darker gray. The darker gray subunit has residues identified in previous publications and the NA active site (in white). Murine epitopes are illustrated in blue (27), magenta (28), and yellow (29). Human epitopes are indicated in orange (14), cyan (31), green (30), and indigo (32). Mutations identified in the EMVs used for this study are highlighted in red and identified using arrows. Views from the top (A), side (B), and bottom (C) of the NA are depicted.