Synthesis and Structural Characterization of Macrocyclic Plasmin Inhibitors.
Wiedemeyer, S.J.A., Wu, G., Pham, T.L.P., Lang-Henkel, H., Perez Urzua, B., Whisstock, J.C., Law, R.H.P., Steinmetzer, T.(2023) ChemMedChem 18: e202200632-e202200632
- PubMed: 36710259 
- DOI: https://doi.org/10.1002/cmdc.202200632
- Primary Citation of Related Structures:  
7THS, 7UAH - PubMed Abstract: 
Two series of macrocyclic plasmin inhibitors with a C-terminal benzylamine group were synthesized. The substitution of the N-terminal phenylsulfonyl group of a previously described inhibitor provided two analogues with sub-nanomolar inhibition constants. Both compounds possess a high selectivity against all other tested trypsin-like serine proteases. Furthermore, a new approach was used to selectively introduce asymmetric linker segments. Two of these compounds inhibit plasmin with K i values close to 2 nM. For the first time, four crystal structures of these macrocyclic inhibitors could be determined in complex with a Ser195Ala microplasmin mutant. The macrocyclic core segment of the inhibitors binds to the open active site of plasmin without any steric hindrance. This binding mode is incompatible with other trypsin-like serine proteases containing a sterically demanding 99-hairpin loop. The crystal structures obtained experimentally explain the excellent selectivity of this inhibitor type as previously hypothesized.
Organizational Affiliation: 
Department of Pharmacy Institute of Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg 6, 35032, Marburg, Germany.