Fig. 5.

Illustration of the proposed binding of HNK to MMP-9. The structure of MMP-9 is presented (PDB code: 1GKC), with a detailed view of the hinge region which delimits the catalytic active site. Molecular modeling has predicted that HNK can bind deeply into the active site cavity, engaging multiple interactions with the protein, notably through 3 hydrogen bonds with the NH groups of Gly-215, Tyr-423 and C = O group of Glu-402 (arrows), plus hydrophobic contacts with several amino acids (italicized, dashed lines), as represented (adapted from [75])