9F9P

CryoEM structure of recombinant Trypanosoma cruzi apo proteasome 20S subunit

Summary for 9F9P

• Entry DOI: 10.2210/pdb9f9p/pdb
• EMDB information: 50258
• Descriptor: Proteasome subunit alpha type, Putative proteasome beta 3 subunit, Proteasome subunit beta, ... (15 entities in total)
• Functional Keywords: proteasome, unknown function
• Biological source: Trypanosoma cruzi; More
• Total number of polymer chains: 28
• Total formula weight: 784676.35

Authors

Rowland, P. (deposition date: 2024-05-08, release date: 2024-12-25, Last modification date: 2025-01-08)

Primary citation

Eadsforth, T.C.,Torrie, L.S.,Rowland, P.,Edgar, E.V.,MacLean, L.M.,Paterson, C.,Robinson, D.A.,Shepherd, S.M.,Thomas, J.,Thomas, M.G.,Gray, D.W.,Postis, V.L.G.,De Rycker, M.
Pharmacological and structural understanding of the Trypanosoma cruzi proteasome provides key insights for developing site-specific inhibitors.
J.Biol.Chem., 301:108049-108049, 2024

PubMed Abstract: The proteasome is considered an excellent drug target for many infectious diseases as well as cancer. Challenges with robust and safe supply of proteasomes from infectious agents, lack of structural information and complex pharmacology due to multiple active sites have hampered progress in the infectious disease space. We recombinantly expressed the proteasome of the protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease, and demonstrate pharmacological equivalence to the native T. cruzi proteasome. Active-site mutant recombinant proteasomes reveal substrate promiscuity for wild-type proteasomes, with important implications for assessing pharmacological responses of active-site selective inhibitors. Using these mutant proteasomes, we show that some selective parasite proteasome inhibitors only partially inhibit the chymotrypsin-like activity, including a newly developed 5-(phenoxymethyl)furan-2-carboxamide-based proteasome inhibitor. In spite of partial inhibition, these compounds remain potent inhibitors of intracellular T. cruzi growth. Drug-resistant mutants provide further insights in drug mode-of-inhibition. We also present the high-resolution CryoEM structures of both native and recombinantly-expressed T. cruzi proteasomes which reveal pharmacologically-relevant differences in the ligand-binding site compared to the related Leishmania proteasome. Furthermore, we show that the trypanosomatid β4/β5 selectivity pocket is not present in the proteasome structures of other protozoan parasites. This work highlights the need, and provides approaches, to precisely assess proteasome substrate selectivity and pharmacology. It enables structure-guided drug discovery for this promising Chagas disease drug target, provides a new chemical starting point for drug discovery, and paves the road for development of robust proteasome drug discovery programmes for other eukaryotic infectious diseases.

PubMed: 39638245
DOI: 10.1016/j.jbc.2024.108049

Experimental method

ELECTRON MICROSCOPY (2.25 Å)