Figure 2.

Molecular structure of human Pin1 (PDB: 1PIN) without ligand binding. Pin1 is predominantly made up of two major domains: WW domain and PPIase domain. Within the WW domain, there exist two loops, namely Loop I and II. As for the PPIase domain, there is a catalytic loop at the catalytic site. There also exists PPIase binding domain where it could bind to the pS/T-P motif apart from the WW domain. In addition, existing between the two domains, there lies an interdomain interface that has been found to be important in Pin1 allosteric regulation.