The cystatin-like fold of the HRG N2 domain. (A) Chain A (in the same orientation as Figure 2) is shown depicting the 5 β-strands (β1-β5) wrapping and twisting around the α-helix (α1). The internal disulfide bridge can be seen linking β4 and β5. Glycosylation at Asn184 and the S-glutathionyl adduct at Cys185 are shown. The wrapping of the β-sheet (β1-β4) round the α-helix (α1) can also be observed. (B) Fo-Fc electron density map showing the S-glutathionyl adduct (GSH1) bound to Cys185 as a mixed disulfide. (C) Fo-Fc electron density map for the carbohydrate chain linked to Asn184, showing the first 3 sugars, NAG1, NAG2, and MAN3. (B-C) Fo-Fc maps (blue chicken wire contoured at 1σ, carve radius 1.6 Å) were calculated from a model that has never contained NAG, MAN, or GSH.