6ssz
From Proteopedia
Structure of the Plasmodium falciparum falcipain 2 protease in complex with an (E)-chalcone inhibitor.
Structural highlights
FunctionFPC2A_PLAF7 Cysteine protease which cleaves native host hemoglobin and globin in the food vacuole during the asexual blood stage (PubMed:10887194, PubMed:15070727, PubMed:15964982, PubMed:16777845, PubMed:19357776, PubMed:25791019). The binding to host hemoglobin is pH-sensitive and only occurs at acidic pH (PubMed:16777845). Cleaves ankyrin and protein 4.1, two components of host erythrocyte membrane cytoskeleton required for the stability of the erythrocyte membrane, and thus may be involved in parasite release (PubMed:11463472). Preferentially cleaves substrates which have an arginine or lysine at the P1 position and a leucine or phenylalanine at the P2 position (PubMed:10887194, PubMed:19357776).[1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedBACKGROUND: Malaria kills over 400,000 people each year and nearly half the world's population live in at-risk areas. Progress against malaria has recently stalled, highlighting the need for developing novel therapeutics. The parasite haemoglobin degradation pathway, active in the blood stage of the disease where malaria symptoms and lethality manifest, is a well-established drug target. A key enzyme in this pathway is the papain-type protease falcipain-2. METHODS: The crystallographic structure of falcipain-2 at 3.45 A resolution was resolved in complex with an (E)-chalcone small-molecule inhibitor. The falcipain-2-(E)-chalcone complex was analysed with reference to previous falcipain complexes and their similarity to human cathepsin proteases. RESULTS: The (E)-chalcone inhibitor binds falcipain-2 to the rear of the substrate-binding cleft. This is the first structure of a falcipain protease where the rear of the substrate cleft is bound by a small molecule. In this manner, the (E)-chalcone inhibitor mimics interactions observed in protein-based falcipain inhibitors, which can achieve high interaction specificity. CONCLUSIONS: This work informs the search for novel anti-malaria therapeutics that target falcipain-2 by showing the binding site and interactions of the medically privileged (E)-chalcone molecule. Furthermore, this study highlights the possibility of chemically combining the (E)-chalcone molecule with an existing active-site inhibitor of falcipain, which may yield a potent and selective compound for blocking haemoglobin degradation by the malaria parasite. The complex of Plasmodium falciparum falcipain-2 protease with an (E)-chalcone-based inhibitor highlights a novel, small, molecule-binding site.,Machin JM, Kantsadi AL, Vakonakis I Malar J. 2019 Dec 2;18(1):388. doi: 10.1186/s12936-019-3043-0. PMID:31791339[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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