9HJI | pdb_00009hji

Structure of Trypanosoma cruzi Prolyl Oligopeptidase in the close state

• PDB DOI: https://doi.org/10.2210/pdb9HJI/pdb
• EM Map EMD-52215: EMDB EMDataResource

• Classification: HYDROLASE
• Organism(s): Trypanosoma cruzi
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): No 


• Deposited: 2024-11-29 Released: 2025-10-01 
• Deposition Author(s): Batra, S., Ragan, T.J., Hesketh, E., Campeotto, I.
• Funding Organization(s): Wellcome Trust, Royal Society

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 3.57 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Cryo-EM led analysis of open and closed conformations of Chagas vaccine candidate TcPOP.

Batra, S., Olmo, F., Ragan, T.J., Kaplan, M., Calvaresi, V., Frank, A.M., Lancey, C., Assadipapari, M., Ying, C., Struwe, W.B., Hesketh, E.L., Kelly, J.M., Barfod, L., Campeotto, I.

(2025) Nat Commun 16: 7164-7164

• PubMed: 40764299 
• DOI: https://doi.org/10.1038/s41467-025-62068-3
• Primary Citation Related Structures: 
  9HJI, 9HJJ


• PubMed Abstract: 
  

  Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, remains a significant global public health concern. Despite its profound health impact in both endemic and non-endemic areas, no vaccine is available, and the existing therapies are outdated, producing severe side effects. The 80 kDa prolyl oligopeptidase of Trypanosoma cruzi (TcPOP) has been identified as a leading candidate for Chagas vaccine development. Here we report the three-dimensional structure of TcPOP in open and closed conformation, at a global resolution of 3.8 and 3.6 Å, respectively, determined using single-particle cryo-electron microscopy. Multiple conformations were observed and further characterized using plasmonic optical tweezers and hydrogen-deuterium exchange mass spectrometry. To assess the immunogenic potential of TcPOP, we immunized female mice and evaluated both polyclonal and monoclonal responses against the TcPOP antigen and its homologues. The anti-TcPOP polyclonal response demonstrates invasion blocking properties via parasite lysis. Polyclonal sera  were cross-reactive with closely-related POPs but not with human homologues. Collectively, our findings provide structural and functional insights necessary to understand the immunogenicity of TcPOP for future Chagas vaccine development.

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Organizational Affiliation: 
• School of Biosciences, Division of Microbiology, Brewing and Biotechnology, University of Nottingham, Sutton Bonington Campus, Loughborough, UK.
Interdisciplinary Biomedical Research Center, School of Science and Technology, Nottingham Trent University, Nottingham, UK.
Department of Parasitology, Faculty of Sciences, University of Granada, Granada, Spain.
Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, UK.
Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK.
Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of Oxford, Oxford, UK.
Department of Biochemistry, University of Oxford, Oxford, UK.
Department of Immunology and Microbiology, Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Advanced Optics & Photonics Laboratory, Department of Engineering, School of Science & Technology, Nottingham Trent University, Nottingham, UK.
Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
School of Biosciences, Division of Microbiology, Brewing and Biotechnology, University of Nottingham, Sutton Bonington Campus, Loughborough, UK. [e-mail].

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors and generated by (software)

Biological Assembly Evidence: electron microscopy

Macromolecule Content 

• Total Structure Weight: 80.36 kDa 
• Atom Count: 5,532 
• Modeled Residue Count: 697 
• Deposited Residue Count: 714 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Prolyl endopeptidase	A	714	Trypanosoma cruzi	Mutation(s): 0  Gene Names: TCPO EC: 3.4.21
UniProt
Find proteins for Q71MD6 (Trypanosoma cruzi) Explore Q71MD6  Go to UniProtKB:  Q71MD6

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 3.57 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

EM Software:

Task	Software Package	Version
MODEL REFINEMENT	PHENIX

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2025-10-01 
Deposition Author(s): Batra, S., Ragan, T.J., Hesketh, E., Campeotto, I.

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Funding Organization	Location	Grant Number
Wellcome Trust	United Kingdom	204801/Z/16/Z
Royal Society	United Kingdom	IESR2232167

Revision History  

• Version 1.0: 2025-10-01
  Type: Initial release