3D structure of hQPCT.

<p>Ribbon representation of the X-ray structure of hQPCT (PDB id 2AFM). The zinc ion is shown by a yellow sphere, the zinc ligands are shown as orange sticks and the two Cys residues responsible for the disulphide bridge formation as green sticks. The loop connecting β1 with β2 is highlighted in red, while those forming the crown-like structure around the zinc are in orange.