Crystal Structure of the Parasite Protease Inhibitor Chagasin in Complex with a Host Target Cysteine Protease.
Chagasin is a protein produced by Trypanosoma cruzi, the parasite that causes Chagas' disease. This small protein belongs to a recently defined family of cysteine protease inhibitors. Although resembling well-known inhibitors like the cystatins in size (110 amino acid residues) and function (they all inhibit papain-like (Cl family) proteases), it has a unique amino acid sequence and structure. We