2H7W

Crystal structure of Chagasin, the endogenous cysteine-protease inhibitor from Trypanosoma cruzi


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.207 

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This is version 1.3 of the entry. See complete history


Literature

Crystal structure of chagasin, the endogenous cysteine-protease inhibitor from Trypanosoma cruzi.

Figueiredo da Silva, A.A.Vieira, L.C.Krieger, M.A.Goldenberg, S.Zanchin, N.I.Guimaraes, B.G.

(2007) J Struct Biol 157: 416-423

  • DOI: 10.1016/j.jsb.2006.07.017
  • Primary Citation of Related Structures:  
    2H7W

  • PubMed Abstract: 
  • Trypanosoma cruzi chagasin belongs to a recently discovered family of cysteine protease inhibitors found in lower eukaryotes and prokaryotes but not in mammals. Chagasin binds tightly to cruzain, the major lysosomal T. cruzi cysteine protease, involved with infectivity and survival of the parasite in mammalian host cells ...

    Trypanosoma cruzi chagasin belongs to a recently discovered family of cysteine protease inhibitors found in lower eukaryotes and prokaryotes but not in mammals. Chagasin binds tightly to cruzain, the major lysosomal T. cruzi cysteine protease, involved with infectivity and survival of the parasite in mammalian host cells. In the scope of a project to characterize proteins diferentially expressed during T. cruzi metacyclogenesis, we have determined the crystal structure of chagasin, which is now the first X-ray structure of a chagasin-like cysteine protease inhibitor to be reported. The structure was solved by the SIRAS method and refined at 1.7A resolution and a comparison with the two NMR structures available revealed some differences in the loops involved in binding to cysteine proteases. The highly flexible loop 4 could be entirely modeled and residues 29-33 from loop 2 form a 3(10)-helix structure that may be important to stabilize the loop conformation. Chagasin crystal structure was docked to the highest resolution structure available of cruzain and a model of chagasin-cruzain interaction was analyzed. The knowledge of the chagasin crystal structure may contribute to the elucidation of the molecular mechanism involved in the inhibition of cruzain and other T. cruzi cysteine proteases.


    Organizational Affiliation

    Centro de Biologia Molecular Estrutural, Laboratório Nacional de Luz Síncrotron, LNLS, P.O. Box 6192, CEP 13084-971, Campinas SP, Brazil.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
ChagasinA, B131Trypanosoma cruziMutation(s): 1 
Gene Names: cha
Find proteins for Q966X9 (Trypanosoma cruzi)
Explore Q966X9 
Go to UniProtKB:  Q966X9
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.207 
  • Space Group: P 31 1 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 48.779α = 90
b = 48.779β = 90
c = 183.602γ = 120
Software Package:
Software NamePurpose
REFMACrefinement
MAR345data collection
MOSFLMdata reduction
CCP4data scaling
SHARPphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-10-10
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-18
    Changes: Refinement description