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Figure 1.
Figure 1. Crystal structures of NA-Fab complexes showing
the different binding site in Mem/98 NA compared to N9 NA.
(a)-(c). The NA (brown) is shown in approximately the same
orientation in each panel. The antibody heavy chain is in blue,
the light chain is in mauve. N-linked carbohydrates are in
green; the long carbohydrate chain is attached to Asn200. The
view is looking parallel with the viral membrane, with the
Pronase cleavage site at the bottom. The stalk would continue
down the page to the viral membrane. (a) Stereo view of the
Mem/98 N2 NA-Mem5 Fab complex. Electron density was not
continuous for the constant domains of Mem5 Fab and only part of
those are included. A sulfate ion (red spheres) marks the active
site. (b) The N9 NA-NC41 Fab complex (PDB 1NCA). Only the Fv
domain of the antibody is shown. (c) N9 NA-NC10 Fab complex (PDB
1NMB). Contacts include the carbohydrate chain attached to
Asn200 of the adjacent subunit, so that chain is included in the
asymmetric unit. (d) Looking down on to the top surface of the
N9 NA tetramer (green) with four Fvs of NC10 bound. (e) The
Mem/98 NA tetramer with four Fvs of Mem5 bound. The images were
prepared using PyMol (DeLano Scientific).
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