Figure 4.

Superposition of the SGSH backbone on those of five related sulfatases: SGSH (red), ASA (orange), ASB (yellow), PAS (blue), GALNS (green) and BcPMH (brown). SGSH shares a common fold with O-sulfatases consisting of a large central β-sheet with decorating helices (‘conserved region’, top); the loops form a more variable region (‘nonconserved region’, bottom). For orientation, the SGSH N-terminus and C-terminus are shown (N and C, respectively), as are some secondary-structure elements (as in Fig. 2 ▶ a) and some atoms in the active site in ball representation: Ca²⁺ (dark grey), phosphate O atoms (orange), FGly C^β (light grey) and free hydroxyl O atom (red).