FIG 2.

Analysis of the N7 and N6 NA active sites compared to group 2 N2 and group 1 N5 NA. N7 (A) and N6 (B) both contain a 340-cavity adjacent to their active site. This 340-cavity has not been found in any other group 1 or group 2 NA structures, including group 2 N2 (PDB ID 1NN2) (C) or group 1 N5 (PDB ID 3SAL) (D). Similar to the bottom of the NA active site cavity, the 340-cavity is highly negatively charged. N7 oseltamivir carboxylate (A) binding and N6 laninamivir (B) binding are virtually identical to those of other group 2 NA structures.