Figure 5
From: Substrate complexes of human dipeptidyl peptidase III reveal the mechanism of enzyme inhibition
Coordination of the catalytic zinc ion in substrate and inhibitor complexes.
(a) Complex with Met-enkephalin (cyan). The zinc ion is represented as a magenta sphere; the Zn-bound water molecule is shown as a red sphere. Interactions with the metal ion are shown as dashed lines. The side chain of Glu-451 shown in grey (not present in the inactive E451A-variant) was modelled based on structure of the unbound enzyme 17. Potential interactions with the zinc ion are shown as green dashed lines. The distance between the carboxylate of the modelled Glu-451 and the carbonyl carbon of the scissile peptide bond is indicated as grey dashed lines. (b) Complex with the synthetic opioid peptide IVYPW (green). The figure was prepared using the program PyMol (http://www.pymol.org/).
