Figure 6 | Scientific Reports

Figure 6

From: The serine proteinase hepsin is an activator of pro-matrix metalloproteinases: molecular mechanisms and implications for extracellular matrix turnover

Figure 6

Structural modelling of hepsin explains poor PAR2 activation. The PAR2 cleavage sequence peptide (SKGR↓SL) is docked into matriptase and hepsin and displayed side-by-side for comparison. The peptide is shown in ball and stick representation, receptor surfaces are coloured by electrostatic potential, H-bonding interactions are indicated with pink dashes and sub-pockets labelled. The binding sites are largely similar and the peptide binds in the same way. The most significant difference is in the S2′ pocket where the deep hydrophobic channel in matriptase better accommodates the Leu sidechain of the peptide compared to the polar shallow pocket in hepsin. The S2 pocket is also a significant point of difference with the peptide Gly residue engaging in Van der Waals contacts with the Phe sidechain in matriptase, which is absent in the more open pocket of hepsin (insets show a close up of the S2 pocket from a different angle with the peptide in a spacefill format, including hydrogen atoms).