Figure 4.

Active-site structure of Ghcol (left and right stereo drawing). Superposition of the active site of the ligand-free Ghcol (pink and cyan for the peptidase upper-half [C1] and lower-half [C2] subdomain, respectively) and Gly-Pro-Hyp-complexed Ghcol (dark pink and dark cyan for C1 and C2 subdomain, respectively). The catalytic zinc ion and the oxygen of water near the zinc ion are shown as a yellow (orange for ligand-free) and cyan sphere, respectively. The peptide is colored in yellow, and PGE (triethylene glycol) found in the ligand-free Ghcol is colored in green. Ghcol, collagenase from Grimontia hollisae strain 1706B.