Fig. 3.

Fourier electron density maps around Gln^H6 in 4C6 Fab: for data sets A to E as described for Fig. 2. For a and b, the glutamine residue was modeled and refined as γ-hydroxyglutamine for data sets A, B, and D and modeled and refined as glutamine for control data sets C and E. As a control (c and d), the glutamine residue was modeled and refined as glutamine for all data sets. (a) 2F_o – F_c maps (blue), contoured at 1.0 σ. (b) F_o – F_c maps, contoured at 3.0 σ (green) and –3.0 σ (red). (c)2F_o – F_c maps (blue), contoured at 1.0 σ.(d) F_o – F_c maps, contoured at 3.0 σ (green).