• Chagas disease;
  • CYP51;
  • drug design;
  • inhibitors;
  • protein structures


Chagas disease is a chronic infection caused by the protozoan parasite Trypanosoma cruzi, manifested in progressive cardiomyopathy and/or gastrointestinal dysfunction. Therapeutic options to prevent or treat Chagas disease are limited. CYP51, the enzyme key to the biosynthesis of eukaryotic membrane sterols, is a validated drug target in both fungi and T. cruzi. Sulfonamide derivatives of 4-aminopyridyl-based inhibitors of T. cruzi CYP51 (TcCYP51), including the sub-nanomolar compound 3, have molecular structures distinct from other validated CYP51 inhibitors. They augment the biologically relevant chemical space of molecules targeting TcCYP51. In a 2.08 Å X-ray structure, TcCYP51 is in a conformation that has been influenced by compound 3 and is distinct from the previously characterized ground-state conformation of CYP51 drug–target complexes. That the binding site was modulated in response to an incoming inhibitor for the first time characterizes TcCYP51 as a flexible target rather than a rigid template.