Figure 3.

Stereoviews of the active sites, showing the interactions involving (a) ThDP and magnesium in AvPOX–FAD–ThDP, (b) AcThDP and magnesium in AvPOX–FAD–ThDP–Pyr and (c) sulfate in AvPOX–FAD–ThDP. The FAD, ThDP/AcThDP and sulfate molecules are shown as cyan, green and yellow stick representations, respectively. The magnesium ions and the water molecules are shown as grey and red spheres, respectively. All residues marked with an asterisk belong to the symmetry-related subunit. The dashed lines indicate hydrogen-bonding and ionic interactions.