Figure 9
Negative difference density. The difference density map from the EDS (a) shows negative density at the -3[sigma] level (indicating absence of the model) for saccharide units 5-6 (HA3) in PDB entry 1loh (Jedrzejas et al., 2002BB26). Saccharide unit 4 of HA2 is present but is partly displaced from density owing to the incorrect placement of the subsequent units 5 and 6. Omit maps (b) provide no electron density consistent with placement of the two HA3 units. The 2.0 Å resolution mFo - DFc map contoured at ±3[sigma] (green/red) and 2mFo - DFc maximum-likelihood omit map contoured at 1[sigma] (blue) are shown. Maps were calculated for a refined model with the ligand atoms omitted.  [article HTML]

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