T. cruzi calreticulin globular domain

Experimental Data Snapshot

  • Resolution: 2.45 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.223 
  • R-Value Observed: 0.225 

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Ligand Structure Quality Assessment 

This is version 1.4 of the entry. See complete history


Structures of parasite calreticulins provide insights into their flexibility and dual carbohydrate/peptide-binding properties.

Moreau, C.Cioci, G.Iannello, M.Laffly, E.Chouquet, A.Ferreira, A.Thielens, N.M.Gaboriaud, C.

(2016) IUCrJ 3: 408-419

  • DOI: https://doi.org/10.1107/S2052252516012847
  • Primary Citation of Related Structures:  
    5HCA, 5HCB, 5HCF, 5LK5

  • PubMed Abstract: 

    Calreticulin (CRT) is a multifaceted protein, initially discovered as an endoplasmic reticulum (ER) chaperone protein, that is essential in calcium metabolism. Various implications in cancer, early development and immunology have been discovered more recently for CRT, as well as its role as a dominant 'eat-me' prophagocytic signal. Intriguingly, cell-surface exposure/secretion of CRT is among the infective strategies used by parasites such as Trypanosoma cruzi , Entamoeba histolytica , Taenia solium , Leishmania donovani and Schistosoma mansoni . Because of the inherent flexibility of CRTs, their analysis by X-ray crystallography requires the design of recombinant constructs suitable for crystallization, and thus only the structures of two very similar mammalian CRT lectin domains are known. With the X-ray structures of two distant parasite CRTs, insights into species structural determinants that might be harnessed to fight against the parasites without affecting the functions of the host CRT are now provided. Moreover, although the hypothesis that CRT can exhibit both open and closed conformations has been proposed in relation to its chaperone function, only the open conformation has so far been observed in crystal structures. The first evidence is now provided of a complex conformational transition with the junction reoriented towards P-domain closure. SAXS experiments also provided additional information about the flexibility of T. cruzi CRT in solution, thus complementing crystallographic data on the open conformation. Finally, regarding the conserved lectin-domain structure and chaperone function, evidence is provided of its dual carbohydrate/protein specificity and a new scheme is proposed to interpret such unusual substrate-binding properties. These fascinating features are fully consistent with previous experimental observations, as discussed considering the broad spectrum of CRT sequence conservations and differences.

  • Organizational Affiliation

    Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS , 38044 Grenoble, France.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Calreticulin, putative,Calreticulin, putative
A, B, C, D, E
A, B, C, D, E, F
271Trypanosoma cruzi strain CL BrenerMutation(s): 0 
Gene Names: Tc00.1047053510685.10
Find proteins for Q4CPZ0 (Trypanosoma cruzi (strain CL Brener))
Explore Q4CPZ0 
Go to UniProtKB:  Q4CPZ0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ4CPZ0
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on BGC

Download Ideal Coordinates CCD File 
J [auth B],
O [auth F]
C6 H12 O6
Query on ACY

Download Ideal Coordinates CCD File 
G [auth A],
H [auth A],
K [auth C],
M [auth E],
N [auth E]
C2 H4 O2
Query on CL

Download Ideal Coordinates CCD File 
I [auth A],
L [auth C]
Experimental Data & Validation

Experimental Data

  • Resolution: 2.45 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.223 
  • R-Value Observed: 0.225 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 79.3α = 95.57
b = 79.38β = 98.69
c = 85.08γ = 119.86
Software Package:
Software NamePurpose
Cootmodel building
XDSdata reduction
XSCALEdata scaling

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
French National Research AgencyFranceANR 09-PIRI-0021

Revision History  (Full details and data files)

  • Version 1.0: 2016-08-31
    Type: Initial release
  • Version 1.1: 2016-11-09
    Changes: Database references
  • Version 1.2: 2016-12-21
    Changes: Database references
  • Version 1.3: 2017-08-30
    Changes: Author supporting evidence
  • Version 1.4: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Derived calculations, Structure summary