title: Combined approaches for drug design points the way to novel proline racemase inhibitor candidates to fight Chagas' disease.
abstract: Chagas' disease is caused by Trypanosoma cruzi, a protozoan transmitted to humans by blood-feeding insects, blood transfusion or congenitally. Previous research led us to discover a parasite proline racemase (TcPRAC) and to establish its validity as a target for the design of new chemotherapies against the disease, including its chronic form. A known inhibitor of proline racemases, 2-pyrrolecarboxylic acid (PYC), is water-insoluble. We synthesized soluble pyrazole derivatives, but they proved weak or inactive TcPRAC inhibitors. TcPRAC catalytic site is too small and constrained when bound to PYC to allow efficient search for new inhibitors by virtual screening. Forty-nine intermediate conformations between the opened enzyme structure and the closed liganded one were built by calculating a transition path with a method we developed. A wider range of chemical compounds could dock in the partially opened intermediate active site models in silico. Four models were selected for known substrates and weak inhibitors could dock in them and were used to screen chemical libraries. Two identified soluble compounds, (E)-4-oxopent-2-enoic acid (OxoPA) and its derivative (E)-5-bromo-4-oxopent-2-enoic acid (Br-OxoPA), are irreversible competitive inhibitors that presented stronger activity than PYC on TcPRAC. We show here that increasing doses of OxoPA and Br-OxoPA hamper T. cruzi intracellular differentiation and fate in mammalian host cells. Our data confirm that through to their binding mode, these molecules are interesting and promising as lead compounds for the development of chemotherapies against diseases where active proline racemases play essential roles.
authors.affiliation: Laboratoire des Processus Infectieux à Trypanosomatidés, Département Infection et Epidémiologie, Institut Pasteur, Paris, France.
authors.forename: Armand
authors.initials: A
authors.lastname: Berneman
authors.forename: Lory
authors.initials: L
authors.lastname: Montout
authors.forename: Sophie
authors.initials: S
authors.lastname: Goyard
authors.forename: Nathalie
authors.initials: N
authors.lastname: Chamond
authors.forename: Alain
authors.initials: A
authors.lastname: Cosson
authors.forename: Simon
authors.initials: S
authors.lastname: d'Archivio
authors.forename: Nicolas
authors.initials: N
authors.lastname: Gouault
authors.forename: Philippe
authors.initials: P
authors.lastname: Uriac
authors.forename: Arnaud
authors.initials: A
authors.lastname: Blondel
authors.forename: Paola
authors.initials: P
authors.lastname: Minoprio
mesh_terms: D000591:Amino Acid Isomerases / Q000037:antagonists & inhibitors*; D014355:Chagas Disease / Q000201:enzymology*; D015195:Drug Design; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D017433:Protein Structure, Secondary; D014344:Trypanocidal Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D014349:Trypanosoma cruzi / Q000472:pathogenicity
chemical_list: D004791:Enzyme Inhibitors; D014344:Trypanocidal Agents; D000591:Amino Acid Isomerases; C022451:proline racemase